docs: update documentation to OKF v0.1 format

docs/api/admin-system.md

@@ -0,0 +1,291 @@
+---
+type: api
+title: Admin System Endpoints
+description: Admin-only destructive System operations: backup download, restore validate/commit, re-authenticated confirmation tokens, reset-scores, and wipe-challenges.
+resource: backend/src/modules/admin/system/admin-system.controller.ts
+tags: [api, admin, system, backup, restore, danger-zone, confirmation-tokens]
+timestamp: 2026-07-23T12:04:50Z
+---
+
+# Overview
+
+All handlers below are mounted under
+`/api/v1/admin/system` and require a JWT-protected admin session
+(`AdminGuard` + `@Roles('admin')`). Every destructive operation is
+gated by a single-use confirmation token issued by the re-authentication
+endpoint:
+
+```
+client ──reauth──▶ POST /confirmations ──token──▶ client
+client ──commit──▶ POST /restore/commit | /scores/reset | /challenges/wipe
+```
+
+The token table is documented at
+[/database/admin-operation-tokens.md](/database/admin-operation-tokens.md).
+
+# Endpoints
+
+| Method | Path                                       | Source                                                    |
+|--------|--------------------------------------------|-----------------------------------------------------------|
+| `GET`  | `/api/v1/admin/system/backup`              | `admin-system.controller.ts` → `BackupService.build()`    |
+| `POST` | `/api/v1/admin/system/restore/validate`    | `admin-system.controller.ts` → `RestoreService.stageArchive()` |
+| `POST` | `/api/v1/admin/system/restore/commit`      | `admin-system.controller.ts` → `RestoreService.commitRestore()` + `AuthService.revokeAllRefreshSessions()` |
+| `POST` | `/api/v1/admin/system/confirmations`       | `admin-system.controller.ts` → `AuthService.reauthenticateAdmin()` + `ConfirmationTokenService.issue()` |
+| `POST` | `/api/v1/admin/system/scores/reset`        | `admin-system.controller.ts` → `DangerZoneService.resetScores()` |
+| `POST` | `/api/v1/admin/system/challenges/wipe`     | `admin-system.controller.ts` → `DangerZoneService.wipeChallenges()` |
+
+## GET /backup
+
+Streams a complete platform snapshot as a JSON attachment. The body has
+the shape:
+
+```jsonc
+{
+  "format": "hipctf-system-backup",
+  "version": 1,
+  "exportedAt": "2026-07-23T12:00:00.000Z",
+  "tables": { "user": [...], "challenge": [...], /* every application table */ },
+  "tableCounts": { "user": 12, "challenge": 4 },
+  "uploads": [
+    { "path": "challenges/foo.bin",
+      "originalFilename": "foo.bin",
+      "sizeBytes": 1024,
+      "sha256": "...", "dataBase64": "..." }
+  ]
+}
+```
+
+Internal tables (`admin_operation_token`, `migrations`, all
+`sqlite_*`) are excluded. The upload root is walked recursively and the
+`.staging` directory is skipped. Files are base64-encoded inline so the
+artifact is a single self-contained JSON file.
+
+The response uses
+`Content-Disposition: attachment; filename="hipctf-backup-<ISO>.json"`.
+
+## POST /restore/validate
+
+Body:
+
+```jsonc
+{ "text": "<raw backup JSON string>" } // or
+{ "archive": { /* already-parsed object */ } }
+```
+
+The body is parsed with a strict zod schema (`RestoreArchiveSchema`).
+Validation enforces:
+
+* `format === 'hipctf-system-backup'`, `version === 1`
+* every upload entry has a safe, non-`..` path, decodes from
+  base64 to exactly `sizeBytes`, and (when provided) matches `sha256`
+* total restored bytes ≤ `BODY_SIZE_LIMIT`
+
+Successful validation returns a `stagingId` plus a summary (sorted
+table list, per-table counts, file count, total bytes, ISO expiresAt):
+
+```jsonc
+{
+  "stagingId": "f0c9...",
+  "expiresAt": "2026-07-23T12:15:00.000Z",
+  "summary": {
+    "tables": ["category", "challenge", "user", /* ... */],
+    "tableCounts": { "user": 12, "challenge": 4 },
+    "files": 3,
+    "totalBytes": 8192
+  }
+}
+```
+
+The stage lives in-memory for `SYSTEM_OP_RESTORE_STAGE_TTL_MS` (default
+15 min) and inside `<DATA_DIR>/.system-staging/restore-<id>/`.
+
+Errors:
+
+* `SYSTEM_RESTORE_VALIDATION_FAILED` (400) — JSON parse, schema, safe
+  path, duplicate path, base64, size mismatch, or checksum mismatch.
+* `SYSTEM_RESTORE_PAYLOAD_TOO_LARGE` (400) — total bytes over
+  `BODY_SIZE_LIMIT`.
+
+## POST /restore/commit
+
+Body:
+
+```jsonc
+{
+  "operation": "restore-backup",
+  "token": "<confirmation token>",
+  "stagingId": "<stage returned from validate>"
+}
+```
+
+Flow:
+
+1. Verifies the admin role and that `operation === 'restore-backup'`.
+2. `ConfirmationTokenService.consume()` verifies the token belongs to
+   this admin, is for `restore-backup`, is unexpired, and is unused.
+3. `RestoreService.commitRestore(stagingId)` builds a new SQLite file
+   by cloning the live DB, then clearing every application table and
+   inserting the archived rows in FK-safe order. Uploads are copied
+   aside as `<UPLOAD_DIR>.restore-stage-<stamp>` and the live
+   database + uploads are swapped atomically via
+   `FilesystemTransactionService.stageSwap()` (with a `restore-backup`
+   rollback handle).
+4. On any failure the swap is rolled back, the staged tree is removed,
+   and the error is mapped to `SYSTEM_RESTORE_ROLLED_BACK` (500).
+5. On success, every refresh token belonging to the current admin is
+   revoked via `AuthService.revokeAllRefreshSessions()` so the SPA is
+   forced back to `/login`.
+
+Returns `{ ok: true, operation: 'restore-backup' }`.
+
+## POST /confirmations
+
+Body:
+
+```jsonc
+{
+  "operation": "restore-backup" | "reset-scores" | "wipe-challenges",
+  "password": "<current admin password>",
+  "stagingId": "<optional, only when restoring>"
+}
+```
+
+Flow:
+
+1. `AuthService.reauthenticateAdmin(userId, password)` verifies the
+   user is still enabled + admin and the Argon2id password matches.
+2. `ConfirmationTokenService.issue()` stores a SHA-256 hash of the
+   generated token and returns the raw token plus its `expiresAt`.
+
+Returns:
+
+```jsonc
+{ "operation": "restore-backup", "token": "<raw>", "expiresAt": "2026-07-23T12:05:00.000Z" }
+```
+
+Errors:
+
+* `SYSTEM_INVALID_CREDENTIALS` (401) — wrong password.
+* `SYSTEM_REAUTH_REQUIRED` (401) — user is no longer admin/disabled.
+
+## POST /scores/reset
+
+Body:
+
+```jsonc
+{ "operation": "reset-scores", "token": "<confirmation token>" }
+```
+
+Consumes a `reset-scores` token, then `DangerZoneService.resetScores()`
+runs a single `DELETE FROM solve` inside a transaction. Returns
+`{ ok: true, solvesRemoved: N }`. Failure maps to `SYSTEM_DANGER_FAILED`
+(500).
+
+## POST /challenges/wipe
+
+Body:
+
+```jsonc
+{ "operation": "wipe-challenges", "token": "<confirmation token>" }
+```
+
+Consumes a `wipe-challenges` token, then
+`DangerZoneService.wipeChallenges()`:
+
+1. Snapshots `<UPLOAD_DIR>/challenges` to `<challengesDir>.wipe-stage-<ts>`.
+2. Runs a SQLite transaction that deletes every `challenge` row
+   (cascading via FK into `challenge_file` and `solve`).
+3. After the DB commits, physically removes the live
+   `<UPLOAD_DIR>/challenges` directory. If the rm fails, the snapshot
+   is copied back into place.
+4. Removes the snapshot only once the live tree is gone.
+
+Returns
+`{ ok: true, challengesRemoved: N, challengeFilesRemoved: M, solvesRemoved: K }`.
+Failure maps to `SYSTEM_DANGER_ROLLED_BACK` (500).
+
+# Error codes
+
+| Code                              | HTTP | Source                                          |
+|-----------------------------------|------|-------------------------------------------------|
+| `SYSTEM_BACKUP_FAILED`            | 500  | `BackupService` table/file read failure          |
+| `SYSTEM_FILE_READ_FAILED`         | 500  | `BackupService` upload walk failure              |
+| `SYSTEM_RESTORE_VALIDATION_FAILED`| 400  | `RestoreService` archive schema/size/sha mismatch |
+| `SYSTEM_RESTORE_PAYLOAD_TOO_LARGE`| 400  | Restored bytes exceed `BODY_SIZE_LIMIT`         |
+| `SYSTEM_RESTORE_STAGE_EXPIRED`    | 400  | `stagingId` missing or expired                   |
+| `SYSTEM_RESTORE_FAILED`           | 500  | Live DB not readable after swap                  |
+| `SYSTEM_RESTORE_ROLLED_BACK`      | 500  | Restore aborted; original state restored         |
+| `SYSTEM_DANGER_FAILED`            | 500  | Reset-scores internal error                      |
+| `SYSTEM_DANGER_ROLLED_BACK`       | 500  | Reset/wipe failed; data unchanged                |
+| `SYSTEM_PAYLOAD_INVALID`          | 400  | `restore/validate` got neither `text` nor `archive` |
+| `SYSTEM_REAUTH_REQUIRED`          | 401  | `reauthenticateAdmin` user no longer admin/enabled |
+| `SYSTEM_INVALID_CREDENTIALS`      | 401  | Wrong password                                   |
+| `SYSTEM_TOKEN_INVALID`            | 400  | Unknown token hash                               |
+| `SYSTEM_TOKEN_EXPIRED`            | 400  | Token `expiresAt` < now                          |
+| `SYSTEM_TOKEN_REUSED`             | 400  | Token already consumed                           |
+| `SYSTEM_TOKEN_MISMATCH`           | 400  | Token issued for a different operation/user       |
+
+# Examples
+
+## Backup → restore on a fresh install
+
+```bash
+# 1. Download a backup
+curl -sS -b cookies.txt -c cookies.txt \
+  -X GET 'http://localhost:3000/api/v1/admin/system/backup' \
+  -o hipctf-backup.json
+
+# 2. Validate (and stage) it
+curl -sS -b cookies.txt -c cookies.txt \
+  -H 'Content-Type: application/json' \
+  -X POST 'http://localhost:3000/api/v1/admin/system/restore/validate' \
+  -d "{\"text\": \"$(cat hipctf-backup.json | python3 -c 'import json,sys;print(json.dumps(sys.stdin.read()))')\"}"
+# => {"stagingId":"<id>", "expiresAt":"...", "summary":{...}}
+
+# 3. Re-authenticate to get a confirmation token
+curl -sS -b cookies.txt -c cookies.txt \
+  -H 'Content-Type: application/json' \
+  -X POST 'http://localhost:3000/api/v1/admin/system/confirmations' \
+  -d '{"operation":"restore-backup","password":"<currentPassword>","stagingId":"<id>"}'
+# => {"operation":"restore-backup","token":"<raw>","expiresAt":"..."}
+
+# 4. Commit
+curl -sS -b cookies.txt -c cookies.txt \
+  -H 'Content-Type: application/json' \
+  -X POST 'http://localhost:3000/api/v1/admin/system/restore/commit' \
+  -d '{"operation":"restore-backup","token":"<raw>","stagingId":"<id>"}'
+```
+
+## Reset scores
+
+```bash
+# 1. Re-auth
+curl -sS ... -d '{"operation":"reset-scores","password":"..."}'  # → token
+# 2. Commit
+curl -sS ... -d '{"operation":"reset-scores","token":"<raw>"}'
+# → {"ok":true,"solvesRemoved":42}
+```
+
+# Wiring
+
+| Concern                      | File                                                                            |
+|------------------------------|---------------------------------------------------------------------------------|
+| Controller                   | `backend/src/modules/admin/system/admin-system.controller.ts`                   |
+| Module                       | `backend/src/modules/admin/system/admin-system.module.ts`                       |
+| Backup                       | `backend/src/modules/admin/system/backup.service.ts`                            |
+| Restore                      | `backend/src/modules/admin/system/restore.service.ts`                           |
+| Confirmation tokens          | `backend/src/modules/admin/system/confirmation-token.service.ts`                |
+| Danger zone                  | `backend/src/modules/admin/system/danger-zone.service.ts`                       |
+| Filesystem swap              | `backend/src/modules/admin/system/filesystem-transaction.service.ts`            |
+| Staging dir helper           | `backend/src/common/utils/upload.ts` (`resolveSystemStagingDir`)                |
+| Password re-auth / revoke    | `backend/src/modules/auth/auth.service.ts` (`reauthenticateAdmin`, `revokeAllRefreshSessions`) |
+| Error codes                  | `backend/src/common/errors/error-codes.ts`                                      |
+| Front-end page               | `frontend/src/app/features/admin/system/system.component.ts`                    |
+| Front-end modal              | `frontend/src/app/features/admin/system/system-confirm-modal.component.ts`      |
+| Front-end service            | `frontend/src/app/features/admin/system/system.service.ts`                      |
+| Front-end pure helpers       | `frontend/src/app/features/admin/system/system.pure.ts`                         |
+| Front-end nav entry          | `frontend/src/app/features/admin/admin-shell.component.ts`                      |
+| Front-end route              | `frontend/src/app/app.routes.ts` (admin child `system`)                         |
+| Cross-store invalidation     | `frontend/src/app/core/services/system-data-change.service.ts`                  |
+| Forced logout helper         | `frontend/src/app/core/services/auth.service.ts` (`forceServerInvalidation`)    |
+| Tests                        | `tests/backend/admin-system-authorization.spec.ts`, `admin-system-backup.spec.ts`, `admin-system-confirmation-token.spec.ts`, `admin-system-danger.spec.ts`, `admin-system-restore-validation.spec.ts`; `tests/frontend/admin-system.pure.spec.ts` |

docs/architecture/backend-modules.md

@@ -27,7 +27,8 @@ also registers two global providers:
 | `UsersModule`    | `backend/src/modules/users/users.module.ts`   | `UsersController` (`/api/v1/auth/register-first-admin`) + `UsersService` (last-admin invariant) + `UsersRankService` (`rankOfUser(manager, userId) -> {rank, points}` over the `solve` table). |
 | `SetupModule`    | `backend/src/modules/setup/setup.module.ts`   | `SetupController` (`POST /api/v1/setup/create-admin`) + `SetupService`. Returns 409 `SYSTEM_INITIALIZED` once any admin exists; serializes concurrent first-admin attempts via an in-process promise chain. |
 | `SystemModule`   | `backend/src/modules/system/system.module.ts` | `SystemController` (`/api/v1/bootstrap`, `/event/status`, SSE streams) + `SystemService`.       |
-| `AdminModule`    | `backend/src/modules/admin/admin.module.ts`   | Four controllers (`AdminController` for `/api/v1/admin/users*`, `AdminGeneralController` for `/api/v1/admin/general/*`, `AdminCategoriesController` for `/api/v1/admin/categories*`, `AdminChallengesController` for `/api/v1/admin/challenges*`) plus their services (`AdminService`, `AdminGeneralService`, `AdminCategoriesService`, `AdminChallengesService`, `ChallengeFilesService`). Gated by `AdminGuard` + `@Roles('admin')`. Imports `TypeOrmModule.forFeature([UserEntity, CategoryEntity, ChallengeEntity, ChallengeFileEntity, SolveEntity])`, `AuthModule`, `UsersModule`, `SettingsModule`, and `CommonModule` (for `SseHubService`, `ThemeLoaderService`). |
+| `AdminModule`    | `backend/src/modules/admin/admin.module.ts`   | Five controllers (`AdminController` for `/api/v1/admin/users*`, `AdminGeneralController` for `/api/v1/admin/general/*`, `AdminCategoriesController` for `/api/v1/admin/categories*`, `AdminChallengesController` for `/api/v1/admin/challenges*`, `AdminSystemController` for `/api/v1/admin/system/*`) plus their services (`AdminService`, `AdminGeneralService`, `AdminCategoriesService`, `AdminChallengesService`, `ChallengeFilesService`, `BackupService`, `RestoreService`, `DangerZoneService`, `FilesystemTransactionService`, `ConfirmationTokenService`). Gated by `AdminGuard` + `@Roles('admin')`. Imports `TypeOrmModule.forFeature([UserEntity, CategoryEntity, ChallengeEntity, ChallengeFileEntity, SolveEntity])`, `AuthModule`, `UsersModule`, `SettingsModule`, `CommonModule` (for `SseHubService`, `ThemeLoaderService`), and `AdminSystemModule` (which adds `AdminOperationTokenEntity` + `AuthModule`). |
+| `AdminSystemModule` | `backend/src/modules/admin/system/admin-system.module.ts` | Hosts the destructive System operations: `AdminSystemController` + `BackupService` + `RestoreService` + `DangerZoneService` + `FilesystemTransactionService` + `ConfirmationTokenService`. Imports `TypeOrmModule.forFeature([AdminOperationTokenEntity])` and `AuthModule` (for `reauthenticateAdmin`/`revokeAllRefreshSessions`). |
 | `UploadsModule`  | `backend/src/modules/uploads/uploads.module.ts` | `UploadsController` (`/api/v1/uploads/*`). Admin-only multipart.                            |
 | `BlogModule`     | `backend/src/modules/blog/blog.module.ts`     | `BlogController`/`BlogService` expose published posts at `GET /api/v1/blog/posts`; `AdminBlogController`/`AdminBlogService` provide guarded CRUD at `/api/v1/admin/blog/posts` using `BlogPostEntity`. |
 | `ChallengesModule` | `backend/src/modules/challenges/challenges.module.ts` | `ChallengesController` (`/api/v1/challenges/{board,status,:id,:id/solves}`) + `ChallengesEventsController` (authenticated SSE `/api/v1/events`) + `ChallengesService` (board, detail, submit, scoring util). |
@@ -44,6 +45,7 @@ also registers two global providers:
 | `AdminGeneralController` | `/api/v1/admin/general` | Admin only | `backend/src/modules/admin/admin-general.controller.ts`      |
 | `AdminCategoriesController` | `/api/v1/admin/categories` | Admin only | `backend/src/modules/admin/admin-categories.controller.ts` |
 | `AdminChallengesController` | `/api/v1/admin/challenges` | Admin only | `backend/src/modules/admin/admin-challenges.controller.ts` |
+| `AdminSystemController` | `/api/v1/admin/system` | Admin only (plus confirmation tokens for destructive ops) | `backend/src/modules/admin/system/admin-system.controller.ts` |
 | `SystemController`     | `/api/v1`               | Mixed (bootstrap/event/scoreboard/settings are public; `events/status` SSE is JWT-protected) | `backend/src/modules/system/system.controller.ts` |
 | `UploadsController`    | `/api/v1/uploads`       | Admin only   | `backend/src/modules/uploads/uploads.controller.ts`          |
 | `BlogController`       | `/api/v1/blog`          | Public       | `backend/src/modules/blog/blog.controller.ts`               |
@@ -91,3 +93,4 @@ also registers two global providers:
 - [Key Files Index](/architecture/key-files.md)
 - [REST API Overview](/api/rest-overview.md)
 - [Blog API](/api/blog.md)
+- [Admin System API](/api/admin-system.md)

docs/architecture/key-files.md

@@ -123,6 +123,36 @@ timestamp: 2026-07-23T10:12:24Z
 | `tests/backend/scoreboard.service.spec.ts` | Service-level tests covering `computeAwardedPoints` parity with `submitFlag`, color-index stability, matrix ordering, and graph state handling. |
 | `tests/frontend/scoreboard.pure.spec.ts` | Pure helpers: `applyRankingSort` (competition-rank numbering), `parseSolveEventIntoRanking` (add-or-increment + sort), `dedupEventLogBySolveId`, `applySolveToGraph` (anchors + plateau + top-10 trim), `mutateMatrixFromSolve`, `stablePlayerColorIndex`, `formatSolveDateTime`. |
 | `tests/frontend/scoreboard.store.spec.ts` | Store lifecycle + live merge: `loadAll` aggregation + idempotency, SSE `solve` frame applying to all four tabs, `stop()` teardown, exponential reconnect. |
+| `backend/src/modules/admin/system/admin-system.controller.ts` | Mounts `/api/v1/admin/system/*` (backup download, restore validate/commit, confirmations, scores/reset, challenges/wipe); all handlers require `AdminGuard` + `@Roles('admin')` and the destructive ones also consume a confirmation token. |
+| `backend/src/modules/admin/system/admin-system.module.ts` | Wires `AdminSystemController`, `BackupService`, `RestoreService`, `DangerZoneService`, `FilesystemTransactionService`, `ConfirmationTokenService`; imports `TypeOrmModule.forFeature([AdminOperationTokenEntity])` and `AuthModule`. |
+| `backend/src/modules/admin/system/backup.service.ts` | Builds the full backup JSON: every application table (`sqlite_master` discovery, excluding `admin_operation_token`/`migrations`/`sqlite_*`), with base64-encoded uploads walked recursively from `UPLOAD_DIR` (skipping `.staging`). Exposes `discoverTables()`, `getUploadDir()`, and `BackupService.stringify(doc)`. |
+| `backend/src/modules/admin/system/restore.service.ts` | Two-phase restore: `stageArchive(rawText, userId)` validates the archive (zod), decodes uploads into `<DATA_DIR>/.system-staging/restore-<id>/`, and returns a summary; `commitRestore(stagingId)` clones the live DB, clears every application table, re-inserts archived rows in FK-safe order, then atomically swaps the live DB + uploads via `FilesystemTransactionService.stageSwap({ name: 'restore-backup', ... })`. On any failure the swap is rolled back and `SYSTEM_RESTORE_ROLLED_BACK` is returned. |
+| `backend/src/modules/admin/system/danger-zone.service.ts` | `resetScores()` deletes every `solve` row transactionally; `wipeChallenges()` snapshots `<UPLOAD_DIR>/challenges` to a side directory, deletes every challenge inside a transaction, physically removes the live `-challenges` directory post-commit, and either deletes the snapshot or restores from it on failure. |
+| `backend/src/modules/admin/system/filesystem-transaction.service.ts` | Generic file/directory swap primitive: `stageSwap({ pairs, hooks })` renames each live path to a rollback location, then renames the staged path into place (with copy+unlink cross-device fallback); `commit(handle)` removes rollback artifacts; `rollback(handle)` restores the original live paths. Provides static helpers `rmSafe`, `copyDirSync`, `ensureDir`. |
+| `backend/src/modules/admin/system/confirmation-token.service.ts` | Issues SHA-256-hashed single-use tokens with `SYSTEM_OP_CONFIRM_TOKEN_TTL_MS` TTL; `consume()` runs in a transaction with conditional `WHERE consumedAt IS NULL` updates so only the first concurrent caller succeeds. `purgeExpired()` deletes expired and >24h-old consumed rows. |
+| `backend/src/modules/admin/system/dto/admin-system.dto.ts` | Re-exports `ADMIN_OPERATION_KINDS` and zod contracts for the re-auth body, danger confirm body, and restore-commit body; declares the backup format identifier + version constants. |
+| `backend/src/database/entities/admin-operation-token.entity.ts` | TypeORM entity and the canonical `ADMIN_OPERATION_KINDS` literal union (`restore-backup`, `reset-scores`, `wipe-challenges`). |
+| `backend/src/database/migrations/1700000000900-AddAdminOperationTokens.ts` | Forward-only migration that creates the `admin_operation_token` table and its three indexes (`uq_admin_op_token_hash`, `idx_admin_op_token_user_op`, `idx_admin_op_token_expiry`). |
+| `backend/src/common/utils/upload.ts` | Adds `resolveSystemStagingDir(config)` (defaults to `<DATA_DIR>/.system-staging`, never nested under `UPLOAD_DIR`) and `getRequestSizeLimit(config)` used by the system endpoints. |
+| `backend/src/config/env.schema.ts` | Adds `SYSTEM_OP_STAGING_DIR`, `SYSTEM_OP_RESTORE_STAGE_TTL_MS` (default 15 min), `SYSTEM_OP_CONFIRM_TOKEN_TTL_MS` (default 5 min). |
+| `backend/src/common/errors/error-codes.ts` | Adds the `SYSTEM_*` error codes used by the system endpoints (`SYSTEM_BACKUP_FAILED`, `SYSTEM_RESTORE_VALIDATION_FAILED`, `SYSTEM_RESTORE_PAYLOAD_TOO_LARGE`, `SYSTEM_RESTORE_STAGE_EXPIRED`, `SYSTEM_RESTORE_FAILED`, `SYSTEM_RESTORE_ROLLED_BACK`, `SYSTEM_OPERATION_IN_PROGRESS`, `SYSTEM_REAUTH_REQUIRED`, `SYSTEM_INVALID_CREDENTIALS`, `SYSTEM_TOKEN_INVALID`, `SYSTEM_TOKEN_EXPIRED`, `SYSTEM_TOKEN_REUSED`, `SYSTEM_TOKEN_MISMATCH`, `SYSTEM_DANGER_FAILED`, `SYSTEM_DANGER_ROLLED_BACK`, `SYSTEM_FILE_READ_FAILED`, `SYSTEM_PAYLOAD_INVALID`). |
+| `backend/src/modules/auth/auth.service.ts` | Adds `reauthenticateAdmin(userId, password)` (Argon2id verify + admin/enabled status check) and `revokeAllRefreshSessions(userId, manager?)` (used after a successful restore to force the SPA back to `/login`). |
+| `tests/backend/admin-system-authorization.spec.ts` | Non-admin JWTs and missing tokens are rejected on every `/api/v1/admin/system/*` endpoint. |
+| `tests/backend/admin-system-backup.spec.ts` | Backup envelope shape, table discovery exclusion, and base64 file inclusion. |
+| `tests/backend/admin-system-confirmation-token.spec.ts` | Issue/consume/expire/reuse/mismatch flow and TTL config. |
+| `tests/backend/admin-system-danger.spec.ts` | Reset-scores and wipe-challenges happy path + DB/file rollback. |
+| `tests/backend/admin-system-restore-validation.spec.ts` | Archive schema validation, base64 size mismatch, sha256 mismatch, safe-path rejection, and duplicate-path rejection. |
+| `frontend/src/app/features/admin/system/system.component.ts` | `/admin/system` smart page: two panels (Database + Danger Zone), backup download, restore pick + validate, confirm modal trigger, and per-operation success/error surfacing + cross-store invalidation. |
+| `frontend/src/app/features/admin/system/system-confirm-modal.component.ts` | Re-authentication + confirmation-phrase modal with operation-specific copy from `system.pure.ts`. |
+| `frontend/src/app/features/admin/system/system.service.ts` | HTTP client for the six `/api/v1/admin/system/*` endpoints. |
+| `frontend/src/app/features/admin/system/system.pure.ts` | Pure helpers: error → friendly message map, `destructiveCopy(op)` per-operation modal copy, `pickRestoreFile()` (jsdom-testable file picker), `deriveBackupFilename()`. |
+| `frontend/src/app/core/services/system-data-change.service.ts` | Root-provided signal bus (`'scores-reset'`, `'challenges-wiped'`, `'restore-completed'`) consumed by `ChallengesStore` and `ScoreboardStore` to invalidate their caches after a destructive operation. |
+| `frontend/src/app/core/services/auth.service.ts` | Adds `forceServerInvalidation()` so the restore flow can drop the local session and broadcast the cross-tab invalidation without invoking the backend logout. |
+| `frontend/src/app/features/challenges/challenges.store.ts` | Now subscribes to `SystemDataChangeService` and calls `reset()` on every destructive operation kind. |
+| `frontend/src/app/features/scoreboard/scoreboard.store.ts` | Now subscribes to `SystemDataChangeService` and clears ranking/matrix/event-log/graph on every destructive operation kind. |
+| `frontend/src/app/features/admin/admin-shell.component.ts` | Side-nav entry for `system` is now `enabled: true`. |
+| `frontend/src/app/app.routes.ts` | Adds the lazy `system` child route under the admin shell. |
+| `tests/frontend/admin-system.pure.spec.ts` | Pure-helper contracts for the friendly error map, destructive copy, and file picker. |
 
 # See also
 
@@ -135,3 +165,6 @@ timestamp: 2026-07-23T10:12:24Z
 - [Notifications](/guides/notifications.md)
 - [Blog Publishing and Reading](/guides/blog.md)
 - [Blog API](/api/blog.md)
+- [Admin System API](/api/admin-system.md)
+- [Admin System Page Guide](/guides/admin-system-page.md)
+- [Admin Operation Tokens Table](/database/admin-operation-tokens.md)

docs/database/admin-operation-tokens-migration.md

@@ -0,0 +1,38 @@
+---
+type: database
+title: Admin Operation Tokens Migration
+description: Forward-only migration that adds the `admin_operation_token` table and its indexes for destructive System-operation confirmation tokens.
+resource: backend/src/database/migrations/1700000000900-AddAdminOperationTokens.ts
+tags: [database, migration, admin, system, tokens]
+timestamp: 2026-07-23T12:04:50Z
+---
+
+# Purpose
+
+Adds the [admin_operation_token](/database/admin-operation-tokens.md)
+table that backs the destructive operations under
+`/api/v1/admin/system/*` (restore-backup, reset-scores,
+wipe-challenges). Always fresh on a new database; on existing instances
+the migration is a no-op if the table already exists.
+
+# Up
+
+1. `CREATE TABLE IF NOT EXISTS admin_operation_token` with the columns
+   listed in the [schema doc](/database/admin-operation-tokens.md#schema).
+2. `CREATE UNIQUE INDEX IF NOT EXISTS uq_admin_op_token_hash` on
+   `token_hash` to make one-shot use enforceable.
+3. `CREATE INDEX IF NOT EXISTS idx_admin_op_token_user_op` on
+   `(user_id, operation)` for fast per-admin lookup.
+4. `CREATE INDEX IF NOT EXISTS idx_admin_op_token_expiry` on
+   `expires_at` so the periodic purge can use an index scan.
+
+# Down
+
+Drops the indexes in reverse order and drops the table.
+
+# Wiring
+
+The migration is registered in
+`backend/src/database/database.module.ts` after the existing user
+triggers migration. The entity is registered in the same `ENTITIES`
+array so `forFeature` lets `AdminSystemModule` inject the repository.

docs/database/admin-operation-tokens.md

@@ -0,0 +1,55 @@
+---
+type: database
+title: Admin Operation Tokens
+description: Single-use confirmation tokens backing the destructive admin System operations (restore-backup, reset-scores, wipe-challenges).
+resource: backend/src/database/entities/admin-operation-token.entity.ts
+tags: [database, admin, system, backup, restore, danger-zone, tokens]
+timestamp: 2026-07-23T12:04:50Z
+---
+
+# Schema
+
+| Column        | Type      | Description                                                                                              |
+|---------------|-----------|----------------------------------------------------------------------------------------------------------|
+| `id`          | TEXT PK   | UUIDv4 generated client-side; the primary key.                                                           |
+| `user_id`     | TEXT FK   | `user.id` of the administrator who issued the token. FK `ON DELETE CASCADE` to `user`.                    |
+| `operation`   | TEXT      | One of `restore-backup`, `reset-scores`, `wipe-challenges` (mirrors `ADMIN_OPERATION_KINDS`).             |
+| `token_hash`  | TEXT      | Hex-encoded SHA-256 of the raw token. The raw token is returned once and never logged or stored. Unique. |
+| `issued_at`   | TEXT      | ISO-8601 timestamp at issuance.                                                                           |
+| `expires_at`  | TEXT      | ISO-8601 timestamp after which the token is invalid (default TTL: `SYSTEM_OP_CONFIRM_TOKEN_TTL_MS`, 5 min). |
+| `consumed_at` | TEXT null | ISO-8601 timestamp when the token was consumed; null while still valid.                                  |
+
+# Indexes
+
+| Index                          | Purpose                                                |
+|--------------------------------|--------------------------------------------------------|
+| `uq_admin_op_token_hash`       | `UNIQUE` on `token_hash` — guarantees one-shot use.    |
+| `idx_admin_op_token_user_op`   | `(user_id, operation)` — fast per-admin/per-op lookup. |
+| `idx_admin_op_token_expiry`    | `expires_at` — enables the periodic expiry sweep.      |
+
+# Lifecycle
+
+1. Admin re-authenticates with their current password via
+   `POST /api/v1/admin/system/confirmations`. The backend verifies the
+   password with Argon2id, then `ConfirmationTokenService.issue()`
+   generates a 32-byte base64url token, persists only its SHA-256 hash,
+   and returns the raw token plus its `expiresAt`.
+2. The client passes the raw token (and the `stagingId` for restores)
+   to the matching destructive endpoint (`/restore/commit`,
+   `/scores/reset`, `/challenges/wipe`).
+3. `ConfirmationTokenService.consume()` runs the consumption inside a
+   transaction: it looks the token up by hash, validates
+   `user_id` + `operation` (+ `stagingId` for restores), checks
+   `expires_at > now`, and finally performs a conditional update
+   `WHERE consumedAt IS NULL` so only the first concurrent caller
+   succeeds. A second attempt returns `SYSTEM_TOKEN_REUSED`.
+4. `purgeExpired()` deletes expired rows and consumed rows older than
+   24h.
+
+# Related
+
+* Migration: [Admin Operation Tokens Migration](/database/admin-operation-tokens-migration.md)
+* Service: `backend/src/modules/admin/system/confirmation-token.service.ts`
+* Error codes: `SYSTEM_TOKEN_INVALID`, `SYSTEM_TOKEN_EXPIRED`,
+  `SYSTEM_TOKEN_REUSED`, `SYSTEM_TOKEN_MISMATCH`
+* [Admin System API](/api/admin-system.md)

docs/database/schema.md

@@ -42,6 +42,7 @@ re-asserts the unique indexes on `system_key` and `abbreviation`.
 | `solve`           | User-solved challenges (scoring ledger).                    |
 | `refresh_token`   | Rotating refresh tokens (hash + revocation).                |
 | `blog_post`       | Markdown blog posts in draft/published states.              |
+| `admin_operation_token` | Single-use confirmation tokens for destructive System operations. |
 
 # Relationships
 
@@ -68,6 +69,7 @@ user ───< refresh_token
 | `solve`          | `uq_solve_challenge_user` (unique), `idx_solve_user`, `idx_solve_challenge` |
 | `refresh_token`  | `idx_refresh_token_user`, unique on `token_hash`  |
 | `blog_post`      | `idx_blog_status_published` (`status`, `published_at`) |
+| `admin_operation_token` | `uq_admin_op_token_hash` (unique on `token_hash`), `idx_admin_op_token_user_op` (`user_id`, `operation`), `idx_admin_op_token_expiry` (`expires_at`) |
 
 # PRAGMAs
 
@@ -91,3 +93,4 @@ On every process start, `DatabaseInitService.init()`:
 - [Challenge Tables](/database/challenges.md)
 - [Auth and Settings Tables](/database/auth-settings.md)
 - [Blog Post Table](/database/blog-posts.md)
+- [Admin Operation Tokens Table](/database/admin-operation-tokens.md)

docs/guides/admin-system-page.md

@@ -0,0 +1,180 @@
+---
+type: guide
+title: Admin — System (Backup, Restore, Danger Zone)
+description: How an admin navigates to /admin/system, creates a backup, stages and commits a restore, resets all scores, and wipes challenges — including the re-authentication confirmation, progress, and side effects.
+tags: [guide, admin, system, backup, restore, danger-zone, confirmation]
+timestamp: 2026-07-23T12:04:50Z
+---
+
+# Navigation
+
+1. Sign in as an admin and open the admin side-nav (see the
+   [Admin Shell guide](/guides/admin-shell.md)).
+2. Click **System** in the side-nav. The route resolves to
+   `/admin/system` and lazily loads the
+   `AdminSystemComponent` standalone component.
+3. The page renders two panels side by side: **Database** (left) and
+   **Danger Zone** (right). On narrow screens they stack vertically.
+
+# Database panel
+
+## Create a backup
+
+1. Click **Create backup** (data-testid `admin-system-create-backup`).
+   A spinner appears inside the button while the request is in flight.
+2. The browser receives a JSON file via `Content-Disposition:
+   attachment; filename="hipctf-backup-YYYY-MM-DD.json"` and the
+   browser download UI saves it to disk.
+3. On success the panel shows a green **Backup ready.** status line
+   (data-testid `admin-system-backup-success`).
+4. On failure the panel shows a red error message under the buttons
+   (data-testid `admin-system-backup-error`). The friendly message
+   comes from `system.pure.ts` and resolves `SYSTEM_BACKUP_FAILED`,
+   `SYSTEM_FILE_READ_FAILED`, `UNAUTHORIZED`, `FORBIDDEN`, etc.
+
+## Restore a backup
+
+1. Click **Restore backup** (data-testid `admin-system-restore-backup`).
+   A hidden file picker opens restricted to `application/json`/`.json`.
+2. Pick a backup JSON file. The progress line shows
+   **Reading selected backup…**, then **Validating backup
+   server-side…** (data-testid `admin-system-restore-progress`).
+3. The server validates the JSON, decodes uploads, and verifies
+   sizes/checksums. On success a summary card appears
+   (data-testid `admin-system-restore-summary`) showing:
+   * Tables detected
+   * Uploaded files
+   * Total bytes
+   * Stage expiry (ISO timestamp)
+4. From the summary card, the admin has two options:
+   * **Discard staged backup** (data-testid
+     `admin-system-discard-restore`) — drops the staged state and
+     resumes from a clean panel.
+   * **Continue to destructive restore…** (data-testid
+     `admin-system-confirm-restore`) — opens the confirmation modal.
+
+### Confirmation modal (restore-backup)
+
+* The modal title is **Restore database?**.
+* The detail paragraph explains that the entire database and uploads
+  will be replaced (the modal's `preserved` line says **Nothing is
+  preserved**).
+* The stage banner explicitly warns: *You will be logged out after
+  restore completes.*
+* The admin must enter their current password and type
+  `RESTORE BACKUP` exactly into the confirmation phrase field.
+* Click **Confirm**. The modal swaps the input fields for a
+  *Working…* spinner.
+* The frontend calls `POST /confirmations` with `{ operation:
+  'restore-backup', password, stagingId }` to receive a single-use
+  token, then immediately calls `POST /restore/commit` with that
+  token and the staging id.
+* On success the SPA calls `AuthService.forceServerInvalidation()`,
+  resets the `UserStore`, and navigates to `/login`. The
+  `ChallengesStore` and `ScoreboardStore` invalidate themselves via
+  the `SystemDataChangeService` `'restore-completed'` event.
+* On failure the modal stays open and shows the resolved error
+  (e.g. `SYSTEM_TOKEN_MISMATCH`, `SYSTEM_RESTORE_ROLLED_BACK`). The
+  database panel also reflects the error inline.
+
+# Danger Zone panel
+
+The danger zone panel is outlined by a dashed red border and contains
+two red buttons:
+
+| Button                                     | Operation           |
+|--------------------------------------------|---------------------|
+| `admin-system-reset-scores`                | `reset-scores`      |
+| `admin-system-wipe-challenges`             | `wipe-challenges`   |
+
+Each button opens the same confirmation modal with operation-specific
+copy:
+
+* **Reset all scores?** — detail lists what is removed
+  (every solve and award), preserved (users, sessions, roles,
+  challenges, categories, etc.). Confirmation phrase: `RESET SCORES`.
+* **Wipe all challenges?** — detail explains that every challenge, its
+  attached files, every solve, and every award are removed, and that
+  every uploaded challenge file on disk is deleted. Preserved:
+  users, sessions, roles, categories, settings, blog posts, and
+  root-level uploads (e.g. the site logo). Confirmation phrase:
+  `WIPE CHALLENGES`.
+
+After the admin enters their password and types the confirmation
+phrase, the SPA re-authenticates to issue a token and then commits the
+operation. The panel shows a green summary
+(`N solve record(s) removed.` or `N challenge(s), M file(s) wiped.`)
+and a toast notification. The corresponding stores
+(`ChallengesStore`, `ScoreboardStore`) automatically reset themselves
+via the `SystemDataChangeService` `scores-reset` and `challenges-wiped`
+events so every open tab sees fresh data.
+
+# Cross-tab invalidation
+
+After any of the destructive operations, the
+`SystemDataChangeService` notifies all subscribers in the same tab via
+an Angular signal. The injected effects in `ChallengesStore` and
+`ScoreboardStore` reset their cached board/matrix/event-log/graph
+data. For a restore, the SPA additionally forces a cross-tab
+invalidation by calling `AuthService.forceServerInvalidation()`,
+which clears the access token and notifies peer tabs via
+`BroadcastChannel` + the `storage`-event fallback so they redirect to
+`/login` as well.
+
+# Error mapping
+
+The pure helper `friendlySystemErrorMessage(op, err)` in
+`system.pure.ts` converts the backend error codes into user-facing
+messages. Notable mappings:
+
+| Backend code                          | UI message                                                                 |
+|---------------------------------------|----------------------------------------------------------------------------|
+| `SYSTEM_REAUTH_REQUIRED`              | "Your session is no longer valid. Please log in again."                    |
+| `SYSTEM_INVALID_CREDENTIALS`          | "The current password is incorrect."                                       |
+| `SYSTEM_TOKEN_INVALID` / `_EXPIRED`   | "Confirmation token is invalid / expired. Re-authenticate and try again."  |
+| `SYSTEM_TOKEN_REUSED`                 | "Confirmation token was already used. Re-authenticate to get a fresh token." |
+| `SYSTEM_TOKEN_MISMATCH`               | "Confirmation token does not match this operation."                        |
+| `SYSTEM_RESTORE_VALIDATION_FAILED`    | "Backup validation failed. No data was changed."                           |
+| `SYSTEM_RESTORE_PAYLOAD_TOO_LARGE`    | "The backup is larger than the configured upload limit."                   |
+| `SYSTEM_RESTORE_STAGE_EXPIRED`        | "The backup staging window expired. Re-upload and validate again."         |
+| `SYSTEM_RESTORE_ROLLED_BACK`          | "Restore failed and was rolled back. Your data is unchanged."              |
+| `SYSTEM_DANGER_ROLLED_BACK`           | "Operation failed and was rolled back. Nothing was changed."               |
+| `SYSTEM_BACKUP_FAILED`                | "Backup could not be generated. No data was changed."                      |
+| `SYSTEM_DANGER_FAILED`                | "Operation could not complete. No data was changed."                       |
+| `SYSTEM_OPERATION_IN_PROGRESS`        | "Another destructive operation is currently running."                      |
+
+# Examples
+
+## Manual restore happy path
+
+1. Download the backup from a known-good environment.
+2. Sign in as the admin on the target environment.
+3. Navigate to `/admin/system`, click **Restore backup**, select the
+   downloaded file.
+4. Verify the summary matches the expected table counts and file
+   counts.
+5. Click **Continue to destructive restore…**, enter the admin
+   password, type `RESTORE BACKUP`, click **Confirm**.
+6. The modal closes, the page shows a brief *Restore complete.
+   Logging out…* toast, and the SPA navigates to `/login`.
+7. Sign in again with the same admin credentials. The data on the
+   target environment now matches the source backup.
+
+## Manual reset happy path
+
+1. Navigate to `/admin/system`.
+2. Click **Reset all scores**, enter the password, type
+   `RESET SCORES`, click **Confirm**.
+3. The danger zone panel shows the number of solve records removed
+   and a toast notifies the operation completed. Refresh the
+   Scoreboard page — every player is back at zero.
+
+## Manual wipe happy path
+
+1. Navigate to `/admin/system`.
+2. Click **Wipe challenges**, enter the password, type
+   `WIPE CHALLENGES`, click **Confirm**.
+3. The danger zone panel shows counts of challenges, files, and
+   solves removed. The Challenges page becomes empty and the
+   `/admin/challenges` list is empty. The `challenges/` folder on
+   disk is also gone.

docs/index.md

@@ -12,7 +12,7 @@ controls, administrator-managed Markdown blog publishing, and public and
 signed-in blog views.
 
 The docs below are organized by purpose so agents can pull just the slice
-they need. Last regenerated 2026-07-23T10:36:45Z.
+they need. Last regenerated 2026-07-23T12:04:50Z.
 
 # Architecture
 
@@ -43,6 +43,11 @@ they need. Last regenerated 2026-07-23T10:36:45Z.
 * [Auth and Settings Tables](/database/auth-settings.md) - `refresh_token`
   and `setting` tables.
 * [Blog Post Table](/database/blog-posts.md) - `blog_post` table.
+* [Admin Operation Tokens Table](/database/admin-operation-tokens.md) -
+  Single-use confirmation tokens for destructive System operations.
+* [Admin Operation Tokens Migration](/database/admin-operation-tokens-migration.md) -
+  Forward-only migration that adds the `admin_operation_token` table
+  and its indexes.
 
 # API
 
@@ -63,6 +68,9 @@ they need. Last regenerated 2026-07-23T10:36:45Z.
   `/events/status` SSE stream.
 * [Uploads Endpoints](/api/uploads.md) - Admin-only multipart uploads for category icons, challenge files, and validated site logos.
 * [Blog Endpoints](/api/blog.md) - Public published-post listing and admin-only post CRUD, validation, and publication behavior.
+* [Admin System Endpoints](/api/admin-system.md) - Admin-only backup
+  download, restore validate/commit, re-authenticated confirmation
+  tokens, reset-scores, and wipe-challenges.
 
 # Guides
 
@@ -87,6 +95,11 @@ they need. Last regenerated 2026-07-23T10:36:45Z.
 * [Admin — Challenges Full-Replace Import](/guides/admin-challenges-import.md) -
   Transactional full-replace semantics, side effects, and the auto-close
   contract of the confirmed challenges import on `/admin/challenges`.
+* [Admin — System (Backup, Restore, Danger Zone)](/guides/admin-system-page.md) -
+  How an admin navigates to `/admin/system`, creates a backup, stages
+  and commits a restore, resets all scores, and wipes challenges,
+  including the re-authentication confirmation flow and cross-tab
+  invalidation.
 * [Authenticated Shell](/guides/authenticated-shell.md) - The header, LED
   + countdown, quick-jump tabs, user menu, and SSE lifecycle that frame
   every signed-in page.