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/storage/migrate.go

@@ -18,11 +18,13 @@ import (
 
 // MigrateRequest holds parameters for migrating app data.
 type MigrateRequest struct {
-	StackName      string   // e.g., "immich"
-	DisplayName    string   // e.g., "Immich"
-	CurrentHDDPath string   // e.g., "/mnt/hdd_placeholder"
-	TargetPath     string   // e.g., "/mnt/hdd_1"
-	HDDMounts      []string // host-side paths to rsync (e.g., ["/mnt/hdd_placeholder/storage/immich"])
+	StackName      string      // e.g., "immich"
+	DisplayName    string      // e.g., "Immich"
+	CurrentHDDPath string      // e.g., "/mnt/hdd_placeholder"
+	TargetPath     string      // e.g., "/mnt/hdd_1"
+	HDDMounts      []string    // host-side paths to rsync (e.g., ["/mnt/hdd_placeholder/storage/immich"])
+	Logger         *log.Logger // Optional logger for debug output
+	Debug          bool        // Enable debug logging
 }
 
 // MigrateProgress tracks migration state.
@@ -82,6 +84,14 @@ func MigrateAppData(
 		return fmt.Errorf("%s: %w", msg, err)
 	}
 
+	dbg := func(format string, args ...interface{}) {
+		if req.Logger != nil && req.Debug {
+			req.Logger.Printf("[DEBUG] MigrateAppData: "+format, args...)
+		}
+	}
+
+	dbg("starting migration: stack=%s from=%s to=%s mounts=%d", req.StackName, req.CurrentHDDPath, req.TargetPath, len(req.HDDMounts))
+
 	// --- Step 1: Validate ---
 	if req.CurrentHDDPath == "" {
 		return fail("validating", "A jelenlegi tárhely nem megadott", fmt.Errorf("empty current HDD path"))
@@ -107,8 +117,11 @@ func MigrateAppData(
 		}
 	}
 
+	dbg("estimated total size: %s (%d bytes)", bytesHuman(totalBytes), totalBytes)
+
 	// Check free space on target
 	freeBytes := getFreeBytes(req.TargetPath)
+	dbg("target free space: %s (%d bytes)", bytesHuman(freeBytes), freeBytes)
 	if freeBytes > 0 && totalBytes > 0 && int64(float64(totalBytes)*1.05) > freeBytes {
 		return fail("validating", fmt.Sprintf(
 			"Nincs elég szabad hely a céltárolón: szükséges ~%s, szabad %s",
@@ -126,15 +139,18 @@ func MigrateAppData(
 	send("stopping", "Alkalmazás leállítva", 10, 0, totalBytes)
 
 	// --- Step 3: rsync ---
+	dbg("starting rsync phase: %d mount(s) to copy", len(req.HDDMounts))
 	var bytesCopied int64
 	for i, srcPath := range req.HDDMounts {
 		// Determine destination path: replace CurrentHDDPath prefix with TargetPath.
 		// H13: Require trailing separator to prevent /mnt/hdd matching /mnt/hdd_backup/data.
 		if srcPath != req.CurrentHDDPath && !strings.HasPrefix(srcPath, req.CurrentHDDPath+"/") {
+			dbg("skipping mount %s (not under %s)", srcPath, req.CurrentHDDPath)
 			continue
 		}
 		relPath := strings.TrimPrefix(srcPath, req.CurrentHDDPath)
 		dstPath := filepath.Join(req.TargetPath, relPath)
+		dbg("rsync %d/%d: %s → %s", i+1, len(req.HDDMounts), srcPath, dstPath)
 
 		// Ensure destination parent exists
 		if err := os.MkdirAll(filepath.Dir(dstPath), 0755); err != nil {
@@ -162,6 +178,7 @@ func MigrateAppData(
 	send("updating", "Konfiguráció frissítése...", 75, bytesCopied, totalBytes)
 
 	// --- Step 4: Update app.yaml HDD_PATH ---
+	dbg("updating config: HDD_PATH %s → %s for stack %s", req.CurrentHDDPath, req.TargetPath, req.StackName)
 	if err := updateFn(req.StackName, req.TargetPath); err != nil {
 		send("rolling_back", "Konfiguráció frissítése sikertelen, visszaállítás...", 0, bytesCopied, totalBytes)
 		_ = startFn(req.StackName)
@@ -178,6 +195,7 @@ func MigrateAppData(
 		return fail("starting", "Alkalmazás indítása sikertelen az új tárolóról", err)
 	}
 
+	dbg("migration completed: stack=%s bytesCopied=%d elapsed=%ds", req.StackName, bytesCopied, int(time.Since(start).Seconds()))
 	send("done",
 		fmt.Sprintf("Áthelyezés kész! Az alkalmazás az új tárolóról fut. (Régi adat: %s, idő: %ds)",
 			req.CurrentHDDPath, int(time.Since(start).Seconds())),