fix: patch basicsr compatibility with torchvision 0.18+

The functional_tensor module was removed in torchvision 0.18+.
Added compatibility shim to create a fake module that basicsr can import.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/processing/models.py

@@ -1,6 +1,7 @@
 """Model management for Real-ESRGAN and GFPGAN."""
 
 import logging
+import sys
 import time
 from pathlib import Path
 from threading import Lock
@@ -10,6 +11,21 @@ import requests
 import torch
 from tqdm import tqdm
 
+# Patch for basicsr compatibility with torchvision 0.18+
+# The functional_tensor module was removed, but basicsr still imports from it
+import torchvision.transforms.functional as TF
+
+if not hasattr(TF, "rgb_to_grayscale"):
+    TF.rgb_to_grayscale = TF.to_grayscale
+
+# Create a fake module to satisfy basicsr's import
+if "torchvision.transforms.functional_tensor" not in sys.modules:
+
+    class FakeFunctionalTensor:
+        rgb_to_grayscale = TF.rgb_to_grayscale
+
+    sys.modules["torchvision.transforms.functional_tensor"] = FakeFunctionalTensor()
+
 from src.config import MODEL_REGISTRY, MODELS_DIR, ModelInfo, config
 
 logger = logging.getLogger(__name__)