Reorder requirements to prioritize pydantic version

Put pydantic and vllm first to ensure pydantic>=2.12.0
is installed before gradio pulls in older version

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

requirements.txt

@@ -1,6 +1,7 @@
+# pydantic first to satisfy vllm>=0.15.0 requirement
+pydantic>=2.12.0
+vllm>=0.4.0
 transformers>=4.40.0
 accelerate>=0.30.0
 gradio>=5.45.0
-vllm>=0.4.0
 torch>=2.2.0
-pydantic>=2.12.0