Fix local performance tests: Handle Django redirects properly

- Add follow=True to Django test client requests to handle redirects
- Fix content length handling for FileResponse objects
- Local performance tests now pass correctly showing ✅ status

This resolves the issue where all avatar generation tests were showing
'Failed' status even though they were working correctly.

scripts/performance_tests.py

@@ -191,7 +191,7 @@ class PerformanceTestRunner:
             # Local testing with Django test client
             if self.client is None:
                 raise RuntimeError("Django test client not initialized")
-            response = self.client.get(url_path)
+            response = self.client.get(url_path, follow=True)
             end_time = time.time()
             duration = (end_time - start_time) * 1000
 
@@ -207,11 +207,19 @@ class PerformanceTestRunner:
                 else:
                     cache_status = "miss"  # Default assumption for first generation
 
+            # Handle content length for different response types
+            content_length = 0
+            if hasattr(response, "content"):
+                content_length = len(response.content) if response.content else 0
+            elif hasattr(response, "streaming_content"):
+                # For FileResponse, we can't easily get content length without consuming the stream
+                content_length = 1  # Just indicate there's content
+
             return {
                 "test": f"{case['default']}_{case['size']}px",
                 "duration_ms": duration,
                 "status_code": response.status_code,
-                "content_length": len(response.content) if response.content else 0,
+                "content_length": content_length,
                 "cache_status": cache_status,
                 "success": response.status_code == 200,
                 "full_url": full_url,