feat: add admin UI frontend and complete backend APIs

- Add Vue 3 frontend with Element Plus
- Implement login, dashboard, tenant management
- Add app configuration, logs viewer, stats pages
- Add user management for admins
- Update Drone CI to build and deploy frontend
- Frontend ports: 3001 (test), 4001 (prod)

backend/app/services/crypto.py

@@ -35,3 +35,8 @@ def decrypt_value(encrypted_value: str) -> str:
     encrypted = base64.urlsafe_b64decode(encrypted_value.encode())
     decrypted = f.decrypt(encrypted)
     return decrypted.decode()
+
+
+# 别名
+encrypt_config = encrypt_value
+decrypt_config = decrypt_value