chore: improve Docker/Podman compatibility and package installation

- Update Claude permissions to allow podman-compose commands
- Improve Dockerfile package installation with poetry-core
- Switch to explicit docker.io image references for Podman compatibility
- Add PYTHONPATH configuration to ensure proper module imports
- Change frontend port from 80 to 8080 for non-root compatibility
- Add initial chat server implementation (main.py)

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

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

src/datacenter_docs/chat/main.py

@@ -0,0 +1,59 @@
+"""
+Chat server stub for development.
+
+TODO: Implement full chat server with WebSocket support.
+Currently this is a minimal stub to allow the development environment to start.
+"""
+import logging
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+# Configure logging
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+# Create FastAPI app
+app = FastAPI(
+    title="Datacenter Documentation Chat Server",
+    description="WebSocket-based chat interface for documentation queries (STUB - NOT IMPLEMENTED)",
+    version="1.0.0",
+)
+
+# Configure CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # In production, restrict this
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+
+@app.get("/health")
+async def health_check():
+    """Health check endpoint."""
+    return {"status": "ok", "service": "chat", "implemented": False}
+
+
+@app.get("/")
+async def root():
+    """Root endpoint."""
+    return {
+        "message": "Chat server stub - not yet implemented",
+        "status": "stub",
+        "todo": "Implement WebSocket chat functionality",
+    }
+
+
+# TODO: Implement WebSocket endpoint for chat
+# @app.websocket("/ws")
+# async def websocket_endpoint(websocket: WebSocket):
+#     await websocket.accept()
+#     # Implement chat logic here
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    logger.info("Starting chat server stub on port 8001...")
+    uvicorn.run(app, host="0.0.0.0", port=8001)