Add React frontend, ZFS pool mapping, and multi-stage Docker build

- Vite + React frontend with dark-themed dashboard, slot grid per
  enclosure, and SMART detail overlay
- ZFS pool membership via zpool status -P
- Multi-stage Dockerfile (Node build + Python runtime)
- Updated docker-compose with network_mode host and healthcheck

routers/drives.py

@@ -2,6 +2,7 @@ from fastapi import APIRouter, HTTPException
 
 from models.schemas import DriveDetail
 from services.smart import get_smart_data
+from services.zfs import get_zfs_pool_map
 
 router = APIRouter(prefix="/api/drives", tags=["drives"])
 
@@ -17,4 +18,7 @@ async def get_drive_detail(device: str):
     if "error" in data:
         raise HTTPException(status_code=502, detail=data["error"])
 
+    pool_map = await get_zfs_pool_map()
+    data["zfs_pool"] = pool_map.get(device)
+
     return DriveDetail(**data)