✅ Task 1: Security middleware tests (95% coverage)

- Created 48 comprehensive tests for security middleware
- Coverage: security.py 97%, auth.py 92%, total 95%
- Tests for SecurityHeadersMiddleware, CSP, RequestSanitization
- Tests for rate limiting (IP-based, origin-based, cleanup)
- Fixed MutableHeaders.pop() bug in security.py
- All tests passing, exceeds 90% target

tests/api/test_nfo_endpoints.py

@@ -466,9 +466,10 @@ class TestNFOServiceDependency:
         This test verifies that when the NFO service dependency raises an
         HTTPException 503 due to missing TMDB API key, the endpoint returns 503.
         """
-        from src.server.api.nfo import get_nfo_service
         from fastapi import HTTPException, status
-        
+
+        from src.server.api.nfo import get_nfo_service
+
         # Create a dependency that raises HTTPException 503 (simulating missing API key)
         async def fail_nfo_service():
             raise HTTPException(