Implement full JBOD monitor frontend from design JSX

- Dark/light theme toggle, grid/table view toggle
- Expanded DriveHealthSummary with wwn, firmware, capacity, SMART
  counters, and computed health_status field
- Drive detail modal with identity, WWN, ZFS membership, SMART health
- 30s auto-refresh

models/schemas.py

@@ -40,11 +40,18 @@ class DriveHealthSummary(BaseModel):
     device: str
     model: str | None = None
     serial: str | None = None
+    wwn: str | None = None
+    firmware: str | None = None
+    capacity_bytes: int | None = None
     smart_healthy: bool | None = None
     smart_supported: bool = True
     temperature_c: int | None = None
     power_on_hours: int | None = None
+    reallocated_sectors: int | None = None
+    pending_sectors: int | None = None
+    uncorrectable_errors: int | None = None
     zfs_pool: str | None = None
+    health_status: str = "healthy"
 
 
 class SlotWithDrive(BaseModel):