chore: full implementation of code review recommendations (security, quality, tests)

vitest.setup.ts

@@ -0,0 +1,7 @@
+import { vi } from 'vitest';
+
+// Set mandatory environment variables for all tests
+process.env.IMMICH_API_URL = 'http://immich.test';
+process.env.IMMICH_API_KEY = 'test-key';
+process.env.AUTH_SECRET = 'test-auth-secret-32-chars-long-min';
+process.env.SITE_TITLE = 'Test Gallery';