fix(15): convert auth service/tests to async PGlite pattern

The executor agents wrote sync SQLite-style calls (.get(), .all(), .run())
instead of the async Postgres pattern established in Phase 14. Fixed:
- auth.service.ts: use await + destructuring for all DB operations
- auth routes: await listApiKeys
- All auth test files: async createTestDb(), await service calls

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/middleware/auth.test.ts

@@ -21,10 +21,10 @@ mock.module("../../src/server/services/oauth.service", () => ({
 // Import middleware AFTER mocks are set up
 const { requireAuth } = await import("../../src/server/middleware/auth");
 
-let db: ReturnType<typeof createTestDb>;
+let db: Awaited<ReturnType<typeof createTestDb>>;
 
-beforeEach(() => {
-	db = createTestDb();
+beforeEach(async () => {
+	db = await createTestDb();
 	mockGetAuth.mockReset();
 	mockGetAuth.mockReturnValue(null);
 	mockVerifyAccessToken.mockReset();