Add authentication features for admin access

- Introduce a new `auth` module with login, logout, and user verification endpoints for a single admin user.
- Update backend routes to require admin authentication for sensitive operations, enhancing security.
- Modify frontend components to include an authentication provider and gate, ensuring only authorized users can access the application.
- Implement a login page for admin access, improving user experience and security management.
- Update API request handling to redirect unauthorized users to the login page, ensuring proper access control.

backend/settings.py

@@ -29,6 +29,15 @@ CORS_ORIGINS = _split(
     os.getenv("CORS_ORIGINS", "http://localhost:3000,http://127.0.0.1:3000")
 )
 
+# ---- Admin auth ----
+ADMIN_USERNAME = os.getenv("ADMIN_USERNAME", "admin")
+ADMIN_PASSWORD = os.getenv("ADMIN_PASSWORD", "znjj189981$")
+AUTH_SECRET_KEY = os.getenv("AUTH_SECRET_KEY", "dev-secret-change-me")
+AUTH_COOKIE_NAME = os.getenv("AUTH_COOKIE_NAME", "ai_video_admin_token")
+AUTH_TOKEN_EXPIRE_MINUTES = int(os.getenv("AUTH_TOKEN_EXPIRE_MINUTES", "1440"))
+AUTH_COOKIE_SECURE = os.getenv("AUTH_COOKIE_SECURE", "false").lower() == "true"
+AUTH_COOKIE_SAMESITE = os.getenv("AUTH_COOKIE_SAMESITE", "lax")
+
 # ---- WebRTC TURN ----
 # TURN_URLS example:
 # turn:182.92.86.220:3478?transport=udp,turn:182.92.86.220:3478?transport=tcp