Fix Dockerfile: use external patch script instead of inline Python

Docker's parser chokes on multi-line Python in RUN. Moved to
scripts/patch_utils.py and COPY + RUN it.

Dockerfile

@@ -40,23 +40,8 @@ RUN sed -i 's/"DeepseekV32ForCausalLM": ("deepseek_v2", "DeepseekV3ForCausalLM")
 
 # Patch process_weights_after_loading to call model._post_quant_fix() after quant setup
 ARG VLLM_LOADER_DIR=/usr/local/lib/python3.12/dist-packages/vllm/model_executor/model_loader
-RUN python3 -c "
-import re
-path = '${VLLM_LOADER_DIR}/utils.py'.replace('\$', '')
-with open(path) as f:
-    src = f.read()
-# Add _post_quant_fix() call at end of process_weights_after_loading
-old = '    if model_config.quantization == \"torchao\":'
-new = '''    # Custom: allow models to run post-quant-init fixes
-    if hasattr(model, '_post_quant_fix'):
-        model._post_quant_fix()
-
-    if model_config.quantization == \"torchao\":'''
-src = src.replace(old, new, 1)
-with open(path, 'w') as f:
-    f.write(src)
-print('Patched process_weights_after_loading')
-"
+COPY scripts/patch_utils.py /tmp/patch_utils.py
+RUN python3 /tmp/patch_utils.py ${VLLM_LOADER_DIR}/utils.py && rm /tmp/patch_utils.py
 
 # Verify
 RUN python3 -c "import torch; print(f'PyTorch {torch.__version__} OK')" && \

scripts/patch_utils.py

@@ -0,0 +1,23 @@
+"""Patch vLLM's process_weights_after_loading to call model._post_quant_fix()
+after all quant methods have set up their attributes."""
+import sys
+
+path = sys.argv[1]
+with open(path) as f:
+    src = f.read()
+
+old = '    if model_config.quantization == "torchao":'
+new = '''    # Custom: allow models to run post-quant-init fixes
+    if hasattr(model, '_post_quant_fix'):
+        model._post_quant_fix()
+
+    if model_config.quantization == "torchao":'''
+
+if old not in src:
+    print(f"WARNING: Could not find patch target in {path}")
+    sys.exit(1)
+
+src = src.replace(old, new, 1)
+with open(path, 'w') as f:
+    f.write(src)
+print('Patched process_weights_after_loading')