test(server): src/config takes fixed test values from the setup file, so suites stop mocking it

tests/setup.ts mocks src/config once with tests/helpers/test-config.ts. A suite that needs other values calls overrideTestConfig(), and the setup file restores the defaults after every case. The 191 per-file factories are gone; config.test.ts takes the real module through vi.unmock, and the few suites that signed tokens with their own literal secret read it from TEST_CONFIG.

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

@@ -1,11 +1,4 @@
-import { describe, it, expect, vi } from 'vitest';
-
-// Inline factory to avoid vi.mock hoisting issue (no imported vars allowed)
-vi.mock('../../../src/config', () => ({
-  JWT_SECRET: 'test-jwt-secret-for-trek-testing-only',
-  ENCRYPTION_KEY: 'a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2',
-  updateJwtSecret: () => {},
-}));
+import { describe, it, expect } from 'vitest';
 
 import {
   encrypt_api_key,