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

models/schemas.py

@@ -32,6 +32,7 @@ class DriveDetail(BaseModel):
     pending_sectors: int | None = None
     uncorrectable_errors: int | None = None
     wear_leveling_percent: int | None = None
+    zfs_pool: str | None = None
     smart_attributes: list[dict] = []
 
 
@@ -43,6 +44,7 @@ class DriveHealthSummary(BaseModel):
     smart_supported: bool = True
     temperature_c: int | None = None
     power_on_hours: int | None = None
+    zfs_pool: str | None = None
 
 
 class SlotWithDrive(BaseModel):