[AZ-512] Admin class inline edit form + PATCH wiring (cy4 batch 16)

Implements the cycle-3-deferred AZ-512 task under the user-authorized
Option B path (MSW-stubbed; live deploy gates at Step 16 on AZ-513).

Code:
- src/features/admin/AdminPage.tsx — inline edit affordance:
  editingId/editForm state, handleStartEdit/Cancel/Update, Enter+Escape
  keyboard handling, colspan row swap when editing, pencil (✎) button
  per row. Full-body PATCH (Risk 2). Single editingId enforces the
  one-row-at-a-time invariant (Risk 3). Disabled buttons during the
  in-flight PATCH (Risk 4). Inline role="alert" on validation/server
  errors (no alert() per Finding B4 anti-pattern).
- src/i18n/{en,ua}.json — `admin.classes` flat → nested with `title`
  + 6 new keys (edit, save, cancel, nameRequired,
  maxSizeMustBePositive, updateFailed). Parity gate FT-P-22 PASS.

Test infrastructure:
- tests/msw/handlers/admin.ts — PATCH /api/admin/classes/:id
  partial-merge handler.
- tests/admin_class_edit.test.tsx — 12 tests covering AC-1..AC-6
  + AC-8 (AC-7 satisfied by static FT-P-22 gate).
- tests/destructive_ux.test.tsx — adjacent-hygiene selector fix
  at 3 call sites: the new ✎ button moved the first-button
  position; targeting × explicitly preserves the existing
  it.fails()/control semantics.

Docs:
- _docs/02_document/components/08_admin/description.md — recorded
  edit affordance + PATCH wiring + AZ-513 cross-workspace note.
- _docs/03_implementation/batch_16_cycle4_report.md
- _docs/03_implementation/implementation_report_admin_class_edit_cycle4.md
- _docs/02_tasks/todo → done — AZ-512 archived.

Quality gates: 32 files / 243 tests / 13 quarantined skips PASS;
all 35 static checks PASS (FT-P-22/23, STC-ARCH-01/02, STC-SEC*,
banned-deps incl. SEC1B/C/D).

Cross-workspace dependency: admin/ AZ-513 (POST + PATCH + DELETE
/classes routes) NOT yet shipped. Step 11 (Run Tests) passes on
stubs; Step 16 (Deploy) holds until AZ-513 lands live. Leftover
record at _docs/_process_leftovers/2026-05-13_az-512-admin-
classes-prereq.md stays open.

Discovered pre-existing bug (NOT bundled): tests/msw/handlers/
admin.ts returns paginate(seedUsers) for GET /api/admin/users,
but AdminPage consumes as flat User[] → users.map crash. Test
files use the same flat-array workaround
destructive_ux.test.tsx documented. Flagged in batch + impl
reports for separate triage.

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

tests/msw/handlers/admin.ts

@@ -56,6 +56,25 @@ export const adminHandlers = [
     return jsonResponse(body)
   }),
 
+  // AZ-512 — PATCH partial-merge over the seeded class. Default-handler
+  // returns the merged shape so the UI's PATCH-then-refetch sequence sees the
+  // updated row. Tests that need 404/5xx semantics override per-scenario.
+  http.patch('/api/admin/classes/:id', async ({ params, request }) => {
+    const idParam = String(params.id)
+    const id = Number(idParam)
+    const body = (await request.json().catch(() => ({}))) as Partial<{
+      name: string
+      shortName: string
+      color: string
+      maxSizeM: number
+      photoMode: number
+    }>
+    const existing =
+      seedClasses.find((c) => String(c.id) === idParam) ??
+      ({ id: Number.isFinite(id) ? id : 0, name: '', shortName: '', color: '#FF0000', maxSizeM: 5, photoMode: 0 } as const)
+    return jsonResponse({ ...existing, ...body, id: existing.id })
+  }),
+
   http.delete('/api/admin/classes/:id', () => noContent()),
 
   http.get('/api/admin/settings', () =>