test: apply suite review improvements (01–11)

- Fix SEC-005: rewrite path traversal test to upload a real file, inject
  traversal filename into DB, and assert the download does not succeed
- Fix SEC-007: rename misleading test description to reflect it tests
  rejection of an invalid token, not acceptance of a valid one
- Delete health.test.ts: all 3 tests were exact duplicates of auth.test.ts
  and misc.test.ts
- Remove duplicate describe blocks from misc.test.ts: Categories endpoint
  (duplicate of categories.test.ts) and App config (duplicate of auth.test.ts)
- Remove TRIP-016 from trips.test.ts: weaker duplicate of TRIP-007 (no body
  assertion)
- Remove API Keys describe block from profile.test.ts: canonical copy lives
  in security.test.ts where it belongs
- Remove avatarUrl describe block from budgetService.test.ts: identical tests
  already exist in authService.test.ts; drop now-unused import
- Add DB verification to ASSIGN-007 and PACK-006 reorder tests: query
  day_assignments / packing_items after PUT reorder to confirm order changed
- Strengthen BUDGET-007/008/009: add member/payer setup and assert concrete
  values (total_paid, per-user balance, flow direction and amount)
- Remove 6 pointless Map-semantics tests from inAppNotificationActions.test.ts;
  keep only the two built-in registration checks
- Remove 5 passthrough tests from queryHelpers.test.ts; keep the 4 tests that
  cover actual flat-to-nested transformation logic

server/tests/unit/services/budgetService.test.ts

@@ -29,7 +29,7 @@ const mockDb = vi.hoisted(() => {
 
 vi.mock('../../../src/db/database', () => mockDb);
 
-import { calculateSettlement, avatarUrl } from '../../../src/services/budgetService';
+import { calculateSettlement } from '../../../src/services/budgetService';
 import type { BudgetItem, BudgetItemMember } from '../../../src/types';
 
 // ── Helpers ──────────────────────────────────────────────────────────────────
@@ -65,22 +65,6 @@ beforeEach(() => {
   setupDb([], []);
 });
 
-// ── avatarUrl ────────────────────────────────────────────────────────────────
-
-describe('avatarUrl', () => {
-  it('returns /uploads/avatars/<filename> when avatar is set', () => {
-    expect(avatarUrl({ avatar: 'photo.jpg' })).toBe('/uploads/avatars/photo.jpg');
-  });
-
-  it('returns null when avatar is null', () => {
-    expect(avatarUrl({ avatar: null })).toBeNull();
-  });
-
-  it('returns null when avatar is undefined', () => {
-    expect(avatarUrl({})).toBeNull();
-  });
-});
-
 // ── calculateSettlement ──────────────────────────────────────────────────────
 
 describe('calculateSettlement', () => {