2026-07-23 03:47:11 +00:00
6 changed files with 236 additions and 17 deletions
@@ -25,7 +25,7 @@ Routes live in `frontend/src/app/app.routes.ts`:

 | Symbol | Path | Responsibility |
 |---|---|---|
-| `HomeComponent` | `frontend/src/app/features/home/home.component.ts` | Smart shell; owns navigation signals, user hydration, change-password flow, event-stream lifecycle, and peer-invalidation subscription. |
+| `HomeComponent` | `frontend/src/app/features/home/home.component.ts` | Smart shell; owns navigation signals, user hydration, change-password flow, event-stream lifecycle, peer-invalidation subscription, and per-session resets of both `UserStore` and `ChallengesStore` (the latter flushes the per-user board cache on logout / SSE unauthorized / peer-logout). |
 | `ShellHeaderComponent` | `frontend/src/app/features/shell/header/shell-header.component.ts` | Renders title, active section, event LED/countdown, and user menu; contains component-scoped LED styling. |
 | `QuickTabsComponent` | `frontend/src/app/features/shell/tabs/quick-tabs.component.ts` | Emits navigation events for Challenges, Scoreboard, and Blog. |
 | `EventStatusStore` | `frontend/src/app/core/services/event-status.store.ts` | Applies event state frames and computes countdown text; re-exports the pure LED color mapping; wires an optional `onUnauthorized` callback for the new SSE `401`/`403` event. |
@@ -33,7 +33,7 @@ Routes live in `frontend/src/app/app.routes.ts`:
 | `AuthService` | `frontend/src/app/core/services/auth.service.ts` | Stores the access token used by the authenticated SSE transport; owns the cross-tab invalidation `BroadcastChannel` + `storage`-event fallback and exposes `clearAndBroadcast` / `onPeerInvalidation`. |
 | `UserStore` | `frontend/src/app/core/services/user.store.ts` | Hydrates the signed-in user and rank data. |
 | `auth-session-events.pure.ts` | `frontend/src/app/core/services/auth-session-events.pure.ts` | Pure cross-tab message encoding/validation and the namespaced channel / storage-key constants. |
-| `ChallengesStore` | `frontend/src/app/features/challenges/challenges.store.ts` | Signal store backing `/challenges`: board payload, event state, per-card solve listeners, SSE solve-frame mutation, submit response application. |
+| `ChallengesStore` | `frontend/src/app/features/challenges/challenges.store.ts` | Signal store backing `/challenges`: board payload, event state, per-card solve listeners, SSE solve-frame mutation, submit response application, public `reset()` for the session-boundary flush, and `setMyUserId(id)` (now returns the previous id and resets whenever the cached state belongs to an unknown or different user). |
 | `ChallengesApiService` | `frontend/src/app/features/challenges/challenges.service.ts` | HTTP wrapper around `/api/v1/challenges/{board,status,:id,:id/solves}` returning `Observable<...>` and translating `HttpErrorResponse` into a typed `ApiErrorEnvelope`. |
 | `challenges.pure.ts` | `frontend/src/app/features/challenges/challenges.pure.ts` | Pure types + helpers for the challenges feature (`BoardCard`, `SolverRow`, `SolveEventPayload`, sorting, parsers, friendly error mapping, `formatDdHhMm`). |
 | `ChallengeCardComponent` / `CategoryColumnComponent` / `ChallengeModalComponent` | `frontend/src/app/features/challenges/` | Presentational components for the board grid, column, and detail modal. |
@@ -74,7 +74,7 @@ on destruction.
 | `frontend/src/app/core/services/authenticated-event-source.service.ts` | Adds Bearer authentication to the browser SSE request, which does not use the Angular HTTP interceptor chain. |
 | `frontend/src/app/core/services/event-status.pure.ts` | Defines the event payload and transport interface. |
 | `frontend/src/app/features/challenges/challenges.page.ts` | `/challenges` smart page; owns gate logic, modal lifecycle, SSE wiring, and the countdown-zero reload. |
-| `frontend/src/app/features/challenges/challenges.store.ts` | Signal store backing `/challenges`: board, event state, per-card solve listeners, SSE solve-frame mutation, submit response application. |
+| `frontend/src/app/features/challenges/challenges.store.ts` | Signal store backing `/challenges`: board, event state, per-card solve listeners, SSE solve-frame mutation, submit response application, public `reset()`, and per-user `setMyUserId` flush. |
 | `tests/frontend/authenticated-event-source.spec.ts` | Regression coverage for authenticated SSE transport behavior. |

 # Event-status pure helpers
@@ -1,9 +1,9 @@
 ---
 type: architecture
 title: Key Files Index
-description: One-line responsibility for important source and contract-test files, including strict event-window validation, the public bootstrap SSE listener, the challenges full-replace import flow, and the authenticated player-facing challenges board.
-tags: [architecture, key-files, event-window, validation, default-challenge-ip, sse, bootstrap, migrations, challenges, import, board, notifications]
-timestamp: 2026-07-23T01:19:00Z
+description: One-line responsibility for important source and contract-test files, including strict event-window validation, the public bootstrap SSE listener, the challenges full-replace import flow, the authenticated player-facing challenges board, and the per-user `solvedByMe` reset on the session boundary.
+tags: [architecture, key-files, event-window, validation, default-challenge-ip, sse, bootstrap, migrations, challenges, import, board, notifications, per-user, session]
+timestamp: 2026-07-23T03:45:00Z
 ---

 # Backend
@@ -52,7 +52,7 @@ timestamp: 2026-07-23T01:19:00Z
 | `frontend/src/app/core/services/bootstrap.service.ts` | Caches and exposes bootstrap state, refreshes it after admin updates, and applies the resolved theme. |
 | `frontend/src/app/core/services/bootstrap.types.ts` | Defines bootstrap/theme payload types and maps theme tokens to CSS custom properties. |
 | `frontend/src/app/core/services/admin.service.ts` | Calls admin settings, theme-list, category, and upload APIs. |
-| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services. |
+| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services; on logout and on session invalidation also calls `challengesStore.reset()` to flush any per-user board cache before navigating to `/login`. |
 | `frontend/src/app/core/services/auth.service.ts` | Signal-backed access token and current-user state; owns the cross-tab invalidation `BroadcastChannel` + `storage`-event fallback. |
 | `frontend/src/app/core/services/auth-session-events.pure.ts` | Pure cross-tab message encoding/validation and namespaced constants used by the auth broadcast channel. |
 | `frontend/src/app/core/services/authenticated-event-source.service.ts` | Fetch-based authenticated SSE transport with frame parsing, abort support, and a separate `'unauthorized'` event for `401`/`403`. |
@@ -60,7 +60,7 @@ timestamp: 2026-07-23T01:19:00Z
 | `frontend/src/app/core/services/bootstrap-event.pure.ts` | Pure helpers for the public bootstrap SSE listener: `isBootstrapGeneralFrame` predicate, SSE line parser, and the `makeBootstrapEventSource` factory (fetch + `ReadableStream` opener with frame buffering and idempotent `close()`). |
 | `frontend/src/app/core/services/event-status.store.ts` | Event state signal store, one-second countdown timer, and the optional `onUnauthorized` callback wiring; exposes `start()`/`stop()`/`closeTransport()` for transport lifecycle and `subscribeReloadAtCountdownZero(handler)` (with `reloadAtCountdownZero(handler)` kept as a back-compat wrapper) so the reload handler is owned by its subscriber rather than the transport. |
 | `frontend/src/app/core/services/event-status.pure.ts` | Event payload types, transport interface (including `'unauthorized'` listener), pure countdown helpers (`formatDdHhMm` returns `DD:HH:mm:ss` and `deriveCountdownText`), and the `LED_COLOR_BY_STATE` map used by the shell LED. |
-| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services, subscribes to peer invalidation, and navigates to `/login` when the session is invalidated elsewhere. |
+| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services, subscribes to peer invalidation, resets both `UserStore` and `ChallengesStore`, and navigates to `/login` when the session is invalidated elsewhere. |
 | `frontend/src/app/features/shell/header/shell-header.component.ts` | Shell title, status LED (size/shape only — color comes from the pure map via `[style.background-color]`), countdown, and user menu. |
 | `frontend/src/app/features/shell/tabs/quick-tabs.component.ts` | Main shell navigation tabs. |
 | `frontend/src/app/features/shell/change-password/change-password-modal.component.ts` | Change-password form modal. |
@@ -73,7 +73,7 @@ timestamp: 2026-07-23T01:19:00Z
 | `tests/frontend/auth-session-events.spec.ts` | Pure tests for cross-tab invalidation message encoding, payload validation, and `storage`-event filtering. |
 | `tests/frontend/admin-challenges-import-autoclose.spec.ts` | Pure helpers (`summarizeImportResult`, `importErrorMessage`) and modal auto-close branch for the confirmed-import handler. |
 | `frontend/src/app/features/challenges/challenges.page.ts` | `/challenges` smart page: gate logic (countdown/running/stopped/unconfigured), modal lifecycle, SSE wiring on `/api/v1/events`, and the page-owned countdown-zero reload (handler registered in the constructor with the disposer wired into `DestroyRef`). |
-| `frontend/src/app/features/challenges/challenges.store.ts` | Signal store: board, event state, per-card solve listeners, SSE solve-frame mutation, submit response application, stop() lifecycle. |
+| `frontend/src/app/features/challenges/challenges.store.ts` | Signal store: board, event state, per-card solve listeners, SSE solve-frame mutation, submit response application, stop() lifecycle, public `reset()` for the session-boundary flush, and `setMyUserId(id)` which now returns the previous id and clears the cache whenever the cached state belongs to an unknown or different user. |
 | `frontend/src/app/features/challenges/challenges.service.ts` | HTTP service for `/api/v1/challenges/{board,status,:id,:id/solves}` returning typed `ApiErrorEnvelope`s. `getDetail` always requests `?include=solvers` so the modal can render the solvers list in one round-trip; `getBoard` only attaches `include=solvers` when the caller opts in. |
 | `frontend/src/app/features/challenges/challenges.pure.ts` | Pure types and helpers (`BoardCard`, `SolverRow`, `SolveEventPayload`, `parseSolveEvent`, `mergeSolveEventIntoSolvers`, `messageForSolveError`, `formatDdHhMm`). |
 | `frontend/src/app/features/challenges/category-column.component.ts` | Renders a single category column (header + cards) on the challenges board. |
@@ -83,7 +83,8 @@ timestamp: 2026-07-23T01:19:00Z
 | `frontend/src/app/core/interceptors/error-notification.interceptor.ts` | Translates `HttpErrorResponse` into friendly messages and pushes them to `NotificationService` (with suppression for `/api/v1/auth/{login,csrf,register}` and `/api/v1/challenges/status`). |
 | `tests/frontend/challenges.pure.spec.ts` | Pure helpers: sorting, parsers, friendly error mapping, `formatDdHhMm` (`DD:HH:mm:ss`). |
 | `tests/frontend/challenges.service.spec.ts` | HTTP-service contract: `getDetail` URL-encodes the id, attaches `?include=solvers`, and forwards `withCredentials: true`. |
-| `tests/frontend/challenges.store.spec.ts` | Signal store: board mutation, live solve merge, listeners, `stop()`. |
+| `tests/frontend/challenges.store.spec.ts` | Signal store: board mutation, live solve merge, listeners, `stop()`. The "marks solvedByMe" and "does not double-count" tests now call `setMyUserId('me-1')` *before* `load()` to exercise the realistic page-mount sequence. |
+| `tests/frontend/challenges.store.reset.spec.ts` | Per-user `solvedByMe` regression suite: `reset()` clears board/detail/myUserId/SSE; switching user id flushes the previous board; **orphan board** (cached with no recorded user id) is cleared when PlayerB's id is set; a non-mine solve never flips `solvedByMe` from `false` to `true`; `applySubmitResponse` takes the server value verbatim. |
 | `tests/frontend/notification-interceptor.spec.ts` | Interceptor suppression rules and friendly message mapping. |
 | `tests/backend/challenges-board.spec.ts` | Board query shape, ordering, `?include=solvers`. |
 | `tests/backend/challenges-status-rest.spec.ts` | `/api/v1/challenges/status` snapshot shape. |
@@ -28,7 +28,14 @@ The first time the page mounts it triggers `ChallengesStore.load()`
 which calls `GET /api/v1/challenges/board`. It also calls
 `GET /api/v1/challenges/status` once to populate the event state
 synchronously, then opens the authenticated SSE stream on
-`/api/v1/events` for live `solve` frames.
+`/api/v1/events` for live `solve` frames`.
+
+The mount order is significant: `ChallengesPage.ngOnInit()` calls
+`store.setMyUserId(user?.id ?? null)` **before** `store.load()`. If the
+singleton's cache belongs to an unknown or different user, `setMyUserId`
+calls `reset()` first so the new board is never blended with a previous
+user's `solvedByMe`. See
+[Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md).

 # How to access (tester steps)

@@ -209,4 +216,5 @@ destruction of the page the SSE source is closed via
 - [System Endpoints](/api/system.md) (legacy `/events/status`)
 - [Scoreboard Stream](/guides/scoreboard-stream.md)
 - [Authenticated Shell](/guides/authenticated-shell.md) (SSE transport)
+- [Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md) (logout/login, peer-tab, SSE-unauthorized reset)
 - [Notifications](/guides/notifications.md) (error interceptor + service)
@@ -0,0 +1,200 @@
+---
+type: guide
+title: Per-User `solvedByMe` Across the Session Boundary
+description: How the `ChallengesStore` signal cache guarantees that PlayerA's solved-by-me flags never leak into PlayerB's view across logout/login, including SSE-unauthorized and peer-logout invalidation.
+tags: [guide, challenges, solvedByMe, session, logout, store, tester]
+timestamp: 2026-07-23T03:45:00Z
+---
+
+# What this feature does
+
+`ChallengesStore` is a `providedIn: 'root'` Angular singleton that survives
+route navigation and SPA reloads. Its board cache holds a `BoardResponse`
+whose cards carry a per-user `solvedByMe: boolean` flag (the `✓` glyph on
+the card and the `You solved this challenge.` modal banner).
+
+Because `solvedByMe` is **server-computed from the JWT-authenticated user**
+(`backend/src/modules/challenges/challenges.service.ts:75-125`), the
+backend has always returned the correct value per request. The risk was
+purely on the frontend: if PlayerA loaded the board, then logged out, and
+PlayerB logged in **before** the new board response arrived, PlayerB could
+briefly see PlayerA's `solvedByMe` flags (or worse, `applySolveEvent`
+from a third-party solve could overwrite PlayerB's `solvedByMe` because
+the store still believed it was PlayerA).
+
+This change closes that gap at three coordinated points:
+
+1. `ChallengesStore.setMyUserId(id)` — now returns the previous id, and
+   whenever the cached state belongs to a different or unknown user, the
+   store calls `reset()` before recording the new id. This catches the
+   "orphan board loaded before the first `setMyUserId`" path (SSR, hot
+   reload, page mount before auth hydration).
+2. `ChallengesStore.reset()` — new public method; stops the SSE source,
+   clears the one-second tick interval, and wipes `_board`,
+   `_selectedDetail`, `_myUserId`, `_error`, `_loading`, the countdown
+   reload handler, and all `solveListeners`.
+3. `HomeComponent.onLogout()` and `HomeComponent.handleSessionInvalidated()`
+   — both now inject `ChallengesStore` and call `challengesStore.reset()`
+   alongside the existing `userStore.reset()`. This guarantees the board
+   cache is cleared on the way out, regardless of whether logout went
+   through the GUI menu or was triggered by a peer-tab broadcast / SSE
+   `401`/`403`.
+
+Additionally, the mutation paths (`applySolveEvent`, `applySubmitResponse`)
+stopped OR-ing `solvedByMe`. They now take the server's authoritative
+value verbatim, so a third-party solve cannot falsely flip a player's
+`solvedByMe` from `false` to `true` even within a single session.
+
+# Why a new concept doc
+
+The fix spans three files that previously did not coordinate
+(`ChallengesStore`, `HomeComponent`, `ChallengesPage`) and adds a public
+`reset()` method to a previously opaque singleton. A tester verifying
+the per-user invariant should not have to diff the store to learn the
+reset rules, and a developer wiring a new "logout-adjacent" feature
+should not have to guess that the challenges board also needs to be
+flushed.
+
+# Tester flows
+
+> The following assume a configured event window with the event in
+> `running` state and at least one challenge (`alpha`) that has been
+> pre-solved by PlayerA.
+
+## User switch via menu logout
+
+1. Sign in as **PlayerA** and navigate to `/challenges`.
+2. Confirm `alpha` shows the `✓` glyph (`.check` inside
+   `[data-testid="challenge-card-alpha"]`) and the success border.
+3. Open the user menu (`[data-testid="user-menu-trigger"]`) and click
+   **Logout**.
+4. The SPA navigates to `/login`; the `ChallengesStore` cache is cleared.
+5. Sign in as **PlayerB** (a different account that has not solved
+   `alpha`).
+6. Navigate to `/challenges`. Confirm `alpha` shows:
+   * `120 pts` and `4 solves` (the global counter — unchanged).
+   * **No** `✓` glyph and **no** success border on the card.
+   * **No** `[data-testid="modal-solved-banner"]` (`You solved this
+     challenge.`) when the card is opened.
+
+## User switch via peer-tab SSE unauthorized
+
+1. Open the SPA in **Tab A** and **Tab B**, both signed in as PlayerA
+   on `/challenges`. `alpha` shows `✓`.
+2. From the server side, revoke PlayerA's refresh-cookie/session (e.g. an
+   admin row-edit or a manual `refresh_token` deletion).
+3. `EventStatusStore`'s SSE reconnect returns `401`. `Tab A` clears state
+   and navigates to `/login`. The `ChallengesStore` cache in `Tab A` is
+   reset.
+4. In **Tab B**, the user menu can also be used to sign out as PlayerB
+   (or wait for the broadcast from Tab A). Confirm the board does not
+   briefly show PlayerA's `solvedByMe` on PlayerB's view during the
+   transition.
+
+## Third-party solve does not flip `solvedByMe`
+
+1. Sign in as **PlayerB**. Confirm `alpha` shows `solvedByMe = false`.
+2. From a second browser session, sign in as **PlayerA** and solve
+   `alpha`. The SSE `solve` frame is broadcast.
+3. In PlayerB's tab, confirm `alpha`'s `✓` does **not** appear, the
+   border does **not** flip to success, and the modal does **not** show
+   the solved banner. `livePoints` and `solveCount` may still update
+   (those are global, not per-user).
+
+## Negative cases
+
+| Action | Expected |
+|---|---|
+| Reload `/challenges` as the same PlayerA | The board cache is preserved across the SPA reload (signal singletons survive), so `alpha` still shows `✓` after the reload completes its `load()`. |
+| Navigate away from `/challenges` and back | The singleton keeps the cache; `alpha` still shows `✓`. |
+| Have PlayerB solve `alpha` for the first time | The submit response drives `applySubmitResponse`; `solvedByMe` flips to `true`, `✓` appears, and the card border flips to success. |
+| Logout PlayerB then log PlayerB back in (same user) | The store is reset on logout, so the new `load()` fetches a fresh board and `solvedByMe` is recomputed by the server. |
+
+# Visual / interactive elements
+
+There are **no new UI controls**. The existing card and modal selectors
+are the regression targets:
+
+| Element | Selector | After user-switch |
+|---|---|---|
+| Solved check | `.check` inside `[data-testid="challenge-card-<uuid>"]` | **Absent** for PlayerB if PlayerA solved it. |
+| Solved border | `[data-testid="challenge-card-<uuid>"]` (border color) | Default border color, not success. |
+| Modal solved banner | `[data-testid="modal-solved-banner"]` | **Absent** for PlayerB. |
+| Awarded banner | `[data-testid="modal-awarded-banner"]` | **Absent** (no award yet for PlayerB). |
+
+# How it works (developer map)
+
+## `ChallengesStore` singleton lifecycle
+
+`ChallengesStore` is `providedIn: 'root'`, so a single instance is
+shared by every consumer (`ChallengesPage`, `HomeComponent`, any future
+feature that injects it). The store never calls `reset()` itself based
+on time — it only resets in response to explicit calls or to a
+`setMyUserId` change.
+
+### `setMyUserId(id: string | null): string | null`
+
+Returns the previous user id (or `null`). If the store currently holds
+cached board or detail data **and** the previous id differs from the new
+id, it calls `reset()` first. The four cases:
+
+| Previous `_myUserId` | New `id` | Cached state present? | Action |
+|---|---|---|---|
+| `null` | `playerB` | No | Just record the id. |
+| `null` | `playerB` | Yes (orphan) | **Reset**, then record. *(new — closes the bug)* |
+| `playerA` | `playerA` | Yes | Just record (re-mount path; keeps cache). |
+| `playerA` | `playerB` | Yes | **Reset**, then record. |
+| `playerA` | `null` | Yes | **Reset**, then record `null`. |
+
+### `reset(): void`
+
+New public method. Calls `stop()` (closes the SSE source, clears the
+1-second tick interval), then nulls every signal and clears
+`solveListeners` and `countdownZeroHandler`. Idempotent.
+
+### Mutation paths take server values verbatim
+
+`applySolveEvent` previously computed
+`solvedByMe: card.solvedByMe || isMine`. This was wrong because if
+`card.solvedByMe` was `true` from a stale cache and `isMine` was `false`
+(a third party solved), it would leave the flag `true`. It is now
+`solvedByMe: isMine ? true : card.solvedByMe`, so a non-mine event can
+never promote `false` → `true`. `applySubmitResponse` no longer ORs
+either — it takes `response.challenge.solvedByMe` directly, since the
+server is authoritative.
+
+## `ChallengesPage` mount
+
+`ChallengesPage.ngOnInit()` now calls
+`this.store.setMyUserId(user?.id ?? null)` (passing `null` explicitly
+when there is no user, instead of the previous `if (user?.id)` guard).
+This ensures the store gets the call even on the unauthenticated edge
+case so the cache-reset decision runs once.
+
+## `HomeComponent` session-boundary reset
+
+`HomeComponent` injects `ChallengesStore` and calls
+`challengesStore.reset()` in two places:
+
+| Trigger | Method |
+|---|---|
+| User clicked Logout in the menu | `onLogout()` (after `await this.auth.logout()`, before `navigateByUrl('/login')`) |
+| Peer-tab broadcast or SSE `401`/`403` | `handleSessionInvalidated()` (alongside `userStore.reset()` and the modal/menu close) |
+
+The `ChallengesStore` is reset **before** navigation so the SPA never
+renders `/challenges` with a stale board.
+
+## Test coverage
+
+| File | What it pins down |
+|---|---|
+| `tests/frontend/challenges.store.reset.spec.ts` | New: `reset()` clears board / detail / myUserId / SSE; `setMyUserId` flushes when switching; **regression for orphan board** (cached board with no recorded user id is cleared when PlayerB's id is set); third-party solve does not flip `solvedByMe`; `applySubmitResponse` takes the server value verbatim. |
+| `tests/frontend/challenges.store.spec.ts` | Updated: the "marks solvedByMe" and "does not double-count" tests now call `setMyUserId('me-1')` *before* `load()`, so they exercise the realistic page-mount sequence. |
+
+# See also
+
+- [Challenges Board](/guides/challenges-board.md)
+- [Challenges Endpoints](/api/challenges.md)
+- [Cross-Tab Authenticated Shell Invalidation](/guides/cross-tab-invalidation.md)
+- [Frontend Structure](/architecture/frontend-structure.md)
+- [Key Files Index](/architecture/key-files.md)
@@ -30,9 +30,11 @@ This change adds a same-browser **cross-tab session-invalidation channel**:
   `sessionStorage` state **without** rebroadcasting, then notifies
   subscribers.
 4. `HomeComponent` subscribes to the new peer-invalidation event, resets
-   `UserStore`, closes any open change-password / user-menu overlays, and
-   navigates to `/login`. A re-entrancy flag prevents duplicate navigations
-   when the originating tab already navigated.
+   both `UserStore` and `ChallengesStore` (so the per-user board cache is
+   never leaked to the next signed-in user), closes any open
+   change-password / user-menu overlays, and navigates to `/login`. A
+   re-entrancy flag prevents duplicate navigations when the originating
+   tab already navigated.
 5. `AuthenticatedEventSourceService` was extended to dispatch a new
   `'unauthorized'` event when the SSE fetch returns `401` or `403`. Generic
   network failures still dispatch `'error'` and do **not** invalidate.
@@ -182,8 +184,10 @@ unhandled by the store; the SPA does not navigate on transport failure.
 * `ngOnDestroy()` calls `eventStatus.stop()` and unsubscribes from
  `onPeerInvalidation`.
 * `handleSessionInvalidated(reason)`:
-  * Calls `userStore.reset()` and closes `changePasswordOpen` /
-    `userMenuOpen` modal signals.
+  * Calls `userStore.reset()` and `challengesStore.reset()` and closes
+    `changePasswordOpen` / `userMenuOpen` modal signals. The challenges
+    reset guarantees the next signed-in user does not briefly see the
+    previous user's `solvedByMe` flags on `/challenges`.
  * Guards re-entry with `navigatingToLogin` and short-circuits when the
    router is already on `/login`.
  * Otherwise awaits `router.navigateByUrl('/login')`.
@@ -199,6 +203,8 @@ unhandled by the store; the SPA does not navigate on transport failure.

 - [Authenticated Shell](/guides/authenticated-shell.md)
 - [Session Restoration on Reload](/guides/session-restoration.md)
+- [Challenges Board](/guides/challenges-board.md)
+- [Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md)
 - [Frontend Structure](/architecture/frontend-structure.md)
 - [REST API Overview](/api/rest-overview.md)
 - [Auth Endpoints](/api/auth.md)
@@ -11,7 +11,7 @@ scoreboard, an event window with a public countdown, theming, and admin
 controls.

 The docs below are organized by purpose so agents can pull just the slice
-they need. Last regenerated 2026-07-23T03:09:36Z.
+they need. Last regenerated 2026-07-23T03:45:00Z.

 # Architecture

@@ -90,6 +90,10 @@ they need. Last regenerated 2026-07-23T03:09:36Z.
 * [Challenges Board](/guides/challenges-board.md) - How a signed-in
  player navigates `/challenges`, opens the modal, submits a flag, and
  watches live solve updates.
+* [Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md) -
+  How `ChallengesStore`, `HomeComponent`, and the challenges page
+  cooperate so PlayerA's `solvedByMe` flags never leak into PlayerB's
+  view across logout/login or peer-tab invalidation.
 * [Change Password](/guides/change-password.md) - How a signed-in user
  changes their own password, including every error branch and the
  refresh-token revocation behavior.