v0.6.0: healthcheck + hub reporting implementation

- Add heartbeat ping (every 5 min, controller alive signal)
- Add backup integrity check (weekly restic check, Sunday 04:00)
- Add Heartbeat + BackupIntegrity fields to PingUUIDsConfig
- Add HubConfig for central hub reporting
- Add report package (types, builder, pusher) for hub push
- Wire hub reporting into scheduler (configurable interval)
- Update controller.yaml.example with new monitoring + hub sections
- Add monitoring/DEPRECATED.md for legacy bash scripts

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

controller/configs/controller.yaml.example

@@ -80,9 +80,11 @@ monitoring:
   enabled: true
   healthchecks_base: "https://status.felhom.eu"
   ping_uuids:
-    db_dump: "CHANGEME-uuid-for-db-dump"
-    backup: "CHANGEME-uuid-for-backup"
-    system_health: "CHANGEME-uuid-for-system-health"
+    heartbeat: ""                                  # Every 5 min — controller process alive
+    system_health: "CHANGEME-uuid-for-system-health"  # Every 5 min — comprehensive system check
+    db_dump: "CHANGEME-uuid-for-db-dump"              # Daily — after database dumps
+    backup: "CHANGEME-uuid-for-backup"                # Daily — after restic snapshot
+    backup_integrity: ""                              # Weekly (Sunday) — restic check
   system_health_interval: "5m"
   health_check_schedule: "06:00"
   thresholds:
@@ -93,6 +95,13 @@ monitoring:
     memory_warn_percent: 85
     temperature_warn_celsius: 75
 
+# --- Central hub (operator dashboard) ---
+hub:
+  enabled: false                                     # Enable central reporting
+  url: "https://hub.felhom.eu"                       # Hub API endpoint
+  api_key: ""                                        # Shared secret for authentication
+  push_interval: "15m"                               # How often to push reports
+
 # --- Self-update ---
 self_update:
   enabled: true