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

docker-compose.yml

@@ -0,0 +1,15 @@
+services:
+  jbod-monitor:
+    build: .
+    image: docker.adamksmith.xyz/jbod-monitor:latest
+    container_name: jbod-monitor
+    restart: unless-stopped
+    privileged: true
+    network_mode: host
+    volumes:
+      - /dev:/dev
+      - /sys:/sys:ro
+      - /run/udev:/run/udev:ro
+    environment:
+      - TZ=America/Denver
+      - UVICORN_LOG_LEVEL=info