v0.15.5: Disaster recovery — Hub-based infra backup, auto-mount, restore UI

Complete DR implementation (TASK2.md Phases 1-4):
- Hub infra-backup push/pull endpoints (controller.yaml, disk layout, stacks)
- Fresh-deployment detection pulls config from Hub, auto-mounts drives by UUID
- Full-page restore UI with drive status, app table, sequential restore
- docker-setup.sh shows DR instructions when customer_id is configured

New files: disk_layout.go, restore_scan.go, restore_app_linux.go,
restore_drives_linux.go, infra_backup.go, infra_pull.go,
handler_restore.go, restore.html

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

TASK.md

@@ -420,6 +420,15 @@ Update the summary to reflect:
 - Show hub status (enabled)
 - Remove the `CUSTOMER_ID` display bug (the "Note: No --customer specified"
   message is inside the `if [[ -n "$CUSTOMER_ID" ]]` block — wrong logic)
+- Add DR/reinstallation note:
+  ```
+  If this is a reinstallation, the controller will automatically:
+    1. Contact the Hub for your previous configuration
+    2. Mount your existing storage drives
+    3. Detect and restore your applications
+
+  Open https://felhom.<DOMAIN> to monitor the restore process.
+  ```
 
 ### 12. Update `print_help()`