feat: drive migration & Tier 2 restic deprecation (v0.18.0)

Phase 1: Deprecate restic as Tier 2 method (rsync only), auto-migrate on startup
Phase 2: Enhanced per-app migration with backup awareness, DB dump copy, auto-cleanup
Phase 3: Full drive migration with decommissioned state, rollback support, wizard UI
Phase 4: Hub report includes decommissioned drive state

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

controller/internal/monitor/healthcheck.go

@@ -172,6 +172,11 @@ func checkProtectedContainers(protected []string) []string {
 
 func checkStoragePaths(paths []settings.StoragePath) (issues, warnings []string) {
 	for _, sp := range paths {
+		// Skip decommissioned paths — no longer in active use
+		if sp.Decommissioned {
+			continue
+		}
+
 		// Skip disconnected paths — handled by the storage watchdog
 		if sp.Disconnected {
 			warnings = append(warnings, fmt.Sprintf("Meghajtó leválasztva: %s (%s)", sp.Label, sp.Path))