v0.24.0 — Pre-testing observability: debug logging, diagnostic dump, startup self-test

- Add [DEBUG] logging across all modules (backup, storage, sync, selfupdate,
  monitor, notify, report, assets, setup) gated behind logging.level: "debug"
- Add /api/debug/dump endpoint returning full controller state JSON (debug only)
- Add startup self-test validating 9 subsystems (Docker, dirs, storage, hub,
  restic repos, metrics DB) with pass/warn/fail summary
- New packages: internal/selftest, internal/util
- Constructor/signature changes: debug bool params, logger params on
  RunHealthCheck and BuildReport, smart watchdog probe logging

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

controller/internal/backup/restore.go

@@ -21,6 +21,10 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 		return fmt.Errorf("invalid snapshot ID: must be 8-64 lowercase hex characters")
 	}
 
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: stack=%s, snapshotID=%s", stackName, snapshotID)
+	}
+
 	// Prevent concurrent operations
 	m.mu.Lock()
 	if m.running {
@@ -39,6 +43,10 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 	hddMounts := m.stackProvider.GetStackHDDMounts(stackName)
 	hasHDD := len(hddMounts) > 0
 
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: %s has %d HDD mount(s), hasHDD=%v", stackName, len(hddMounts), hasHDD)
+	}
+
 	// Build list of paths to restore from the snapshot
 	var restorePaths []string
 
@@ -47,16 +55,25 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 	if ok {
 		stackDir := filepath.Dir(composePath)
 		restorePaths = append(restorePaths, stackDir)
+		if m.isDebug() {
+			m.logger.Printf("[DEBUG] RestoreApp: will restore config dir: %s", stackDir)
+		}
 	}
 
 	// Restore DB dump files for this stack (per-drive path)
 	drivePath := m.GetAppDrivePath(stackName)
 	dumpDir := AppDBDumpPath(drivePath, stackName)
 	restorePaths = append(restorePaths, dumpDir)
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: will restore DB dump dir: %s", dumpDir)
+	}
 
 	// Restore HDD data (always included for apps that have it — backup is mandatory)
 	if hasHDD {
 		restorePaths = append(restorePaths, hddMounts...)
+		if m.isDebug() {
+			m.logger.Printf("[DEBUG] RestoreApp: will restore HDD data: %v", hddMounts)
+		}
 	}
 
 	if len(restorePaths) == 0 {
@@ -66,17 +83,30 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 	// Use the app's primary restic repo
 	repoPath := PrimaryResticRepoPath(drivePath)
 
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: using repo=%s, %d restore path(s)", repoPath, len(restorePaths))
+	}
+
 	m.logger.Printf("[WARN] RESTORE starting: stack=%s, snapshot=%s, repo=%s, paths=%v, hasHDD=%v",
 		stackName, snapshotID, repoPath, restorePaths, hasHDD)
 
 	// Stop the app before restore
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: step 1/4 — stopping app %s", stackName)
+	}
 	if err := m.stackProvider.StopStack(stackName); err != nil {
 		m.logger.Printf("[WARN] RESTORE could not stop %s: %v (proceeding anyway)", stackName, err)
 	}
 
 	// Execute restore via restic
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: step 2/4 — restoring data from snapshot %s", snapshotID)
+	}
 	if err := m.restic.RestoreAppData(repoPath, snapshotID, restorePaths); err != nil {
 		m.logger.Printf("[ERROR] RESTORE failed for %s: %v", stackName, err)
+		if m.isDebug() {
+			m.logger.Printf("[DEBUG] RestoreApp: step 3/4 — restarting app %s after failure", stackName)
+		}
 		if startErr := m.stackProvider.StartStack(stackName); startErr != nil {
 			m.logger.Printf("[WARN] RESTORE could not restart %s after failure: %v", stackName, startErr)
 		}
@@ -84,6 +114,9 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 	}
 
 	// Restart the app
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: step 3/4 — restarting app %s after successful restore", stackName)
+	}
 	if err := m.stackProvider.StartStack(stackName); err != nil {
 		m.logger.Printf("[WARN] RESTORE could not restart %s after restore: %v", stackName, err)
 	}
@@ -92,6 +125,9 @@ func (m *Manager) RestoreApp(stackName, snapshotID string) error {
 	if hasHDD {
 		restoreType = "full (config+DB+userdata)"
 	}
+	if m.isDebug() {
+		m.logger.Printf("[DEBUG] RestoreApp: step 4/4 — restore completed, type=%s", restoreType)
+	}
 	m.logger.Printf("[INFO] RESTORE completed: stack=%s, snapshot=%s, type=%s", stackName, snapshotID, restoreType)
 	return nil
 }