feat(13-03): add Format check CI step; remove stale no-op lint comment

- Insert 'Format check: pnpm format:check' after Lint in fast-checks job
- Remove the 3-line comment that said lint was a no-op (no longer true)
- Step order: Install → Lint → Format check → Typecheck → PWA unit tests
- Branch-protection contexts (name:CI, fast-checks, api, harness) unchanged

.gitea/workflows/ci.yml

@@ -25,12 +25,12 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
-      # lint is currently a no-op: no package defines a `lint` script and ESLint is
-      # not installed. `pnpm -r lint` prints ERR_PNPM_RECURSIVE_RUN_NO_SCRIPT but
-      # exits 0, so this step passes. Wiring lint is out of this phase's scope.
       - name: Lint
         run: pnpm lint
 
+      - name: Format check
+        run: pnpm format:check
+
       - name: Typecheck
         run: pnpm typecheck