[AZ-510] Auth bootstrap: POST refresh + chained /users/me

Replace the broken `GET /api/admin/auth/refresh` (no `credentials:'include'`)
mount-time bootstrap with `POST /api/admin/auth/refresh` (with credentials)
chained to `GET /api/admin/users/me`. Returning users with a valid HttpOnly
refresh cookie no longer flash through `/login`. Closes Finding B3 / Vision P3.

- Add module-scoped `bootstrapInflight` guard (StrictMode double-mount safety)
  + test-only reset hook exported via the `src/auth` barrel; `tests/setup.ts`
  resets it in `afterEach` to prevent pending-promise leakage between tests.
- Defensive `hasPermission` against legacy `/users/me` payloads omitting
  `permissions`; default MSW handler now seeds `permissions` explicitly.
- Add `endpoints.admin.usersMe()` builder (STC-ARCH-02 forbids the literal).
- Bulk-swap 15 test files from `http.get` -> `http.post` for the refresh
  override so intentional bootstrap-fail tests still fail correctly.
- Update auth component description; mark B3 closed.
- Code review verdict PASS; static + fast suites green (231 / 13 skipped).

Batch report: _docs/03_implementation/batch_13_cycle3_report.md

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/bulk_validate.test.tsx

@@ -78,7 +78,7 @@ function rigDatasetAndBulk(): SyncRig {
   const validatedAfterPost = { current: false }
 
   server.use(
-    http.get('/api/admin/auth/refresh', () => new Response(null, { status: 401 })),
+    http.post('/api/admin/auth/refresh', () => new Response(null, { status: 401 })),
     http.get('/api/flights', () => jsonResponse(paginate([], 1, 1000))),
     http.get('/api/annotations/settings/user', () => new Response(null, { status: 404 })),
     http.put('/api/annotations/settings/user', () => new Response(null, { status: 200 })),