feat: add virtual environment support for Python services

- Update supervisord.conf to use venv Python executables for orchestrator and webdav-sync
- Add virtual environment setup to arty.yml setup/python-env script
- Isolate dependencies for webdav-sync, model-orchestrator, and vllm services
- Fixes dependency conflicts between services (pydantic versions)

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

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

supervisord.conf

@@ -41,7 +41,7 @@ stopwaitsecs=30
 
 # AI Model Orchestrator
 [program:orchestrator]
-command=python3 model-orchestrator/orchestrator_subprocess.py
+command=model-orchestrator/venv/bin/python model-orchestrator/orchestrator_subprocess.py
 directory=.
 autostart=false
 autorestart=true
@@ -58,7 +58,7 @@ stopwaitsecs=30
 
 # ComfyUI WebDAV Sync Service
 [program:webdav-sync]
-command=python3 webdav_sync.py
+command=webdav-sync/venv/bin/python webdav_sync.py
 directory=webdav-sync
 autostart=true
 autorestart=true