docs: update documentation to OKF v0.1 format

docs/database/category-repair-migration.md

@@ -8,7 +8,8 @@ timestamp: 2026-07-22T16:44:54Z
 
 # Purpose
 
-Some persistent `/data/hipctf/db.sqlite` databases were created before
+Some persistent HIPCTF databases (default path
+[`./data/db.sqlite`](/database/schema.md)) were created before
 the canonical six system categories existed. They contain a legacy
 six-column `category` table (no `created_at` / `updated_at`) and
 system rows whose `system_key` / `abbreviation` no longer match the

docs/database/schema.md

@@ -10,8 +10,9 @@ timestamp: 2026-07-22T16:44:54Z
 
 HIPCTF uses **SQLite via better-sqlite3** with TypeORM migrations. The
 database is a single file (`DATABASE_PATH`, default
-`/data/hipctf/db.sqlite`) running in **WAL journal mode** for better
-concurrent read/write performance.
+`./data/db.sqlite`, resolved relative to the process working directory)
+running in **WAL journal mode** for better concurrent read/write
+performance.
 
 The schema is created by a single migration
 (`backend/src/database/migrations/1700000000000-InitSchema.ts`) and seeded