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/overview.py

@@ -11,6 +11,7 @@ from models.schemas import (
 )
 from services.enclosure import discover_enclosures, list_slots
 from services.smart import get_smart_data
+from services.zfs import get_zfs_pool_map
 
 logger = logging.getLogger(__name__)
 
@@ -21,6 +22,7 @@ router = APIRouter(prefix="/api/overview", tags=["overview"])
 async def get_overview():
     """Aggregate view of all enclosures, slots, and drive health."""
     enclosures_raw = discover_enclosures()
+    pool_map = await get_zfs_pool_map()
 
     enc_results: list[EnclosureWithDrives] = []
     total_drives = 0
@@ -74,6 +76,7 @@ async def get_overview():
                     smart_supported=sd.get("smart_supported", True),
                     temperature_c=sd.get("temperature_c"),
                     power_on_hours=sd.get("power_on_hours"),
+                    zfs_pool=pool_map.get(sd["device"]),
                 )
             elif s["populated"]:
                 total_drives += 1