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/setup/handlers.go

@@ -73,6 +73,11 @@ func NewServer(cfg *config.Config, dataDir string, logger *log.Logger, version s
 	return s
 }
 
+// isDebug returns true if logging level is "debug".
+func (s *Server) isDebug() bool {
+	return s.cfg != nil && s.cfg.Logging.Level == "debug"
+}
+
 func (s *Server) loadTemplates() {
 	s.tmpl = template.Must(
 		template.New("").Funcs(template.FuncMap{
@@ -311,6 +316,9 @@ func (s *Server) processHubRestore(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if s.isDebug() {
+		s.logger.Printf("[DEBUG] Setup: hub restore — pulling recovery from %s for customer %s", hubURL, customerID)
+	}
 	recovery, err := report.PullRecovery(hubURL, customerID, password)
 	if err != nil {
 		var msg string
@@ -328,6 +336,10 @@ func (s *Server) processHubRestore(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if s.isDebug() {
+		s.logger.Printf("[DEBUG] Setup: hub recovery received — hasInfra=%v, configLen=%d", recovery.HasInfraBackup, len(recovery.ConfigYAML))
+	}
+
 	// Store recovery data in state for restore execution
 	s.state.SelectedBackup = &SelectedBackup{
 		Source:     "hub",
@@ -392,6 +404,9 @@ func (s *Server) processFreshHub(w http.ResponseWriter, r *http.Request) {
 	s.logger.Printf("[INFO] Setup: config downloaded (%d bytes), writing config...", len(configYAML))
 
 	// Write config and finish setup
+	if s.isDebug() {
+		s.logger.Printf("[DEBUG] Setup: writing fresh config (%d bytes)", len(configYAML))
+	}
 	s.state.SetFormField("retrieval_password", password)
 	if err := s.writeFreshConfig(configYAML, password); err != nil {
 		s.logger.Printf("[ERROR] Setup: writeFreshConfig failed: %v", err)
@@ -447,6 +462,9 @@ func (s *Server) processManual(w http.ResponseWriter, r *http.Request) {
 
 	// Generate controller.yaml
 	configYAML := s.generateManualConfig()
+	if s.isDebug() {
+		s.logger.Printf("[DEBUG] Setup: generated manual config (%d bytes) for customer %s", len(configYAML), customerID)
+	}
 	if err := s.writeFreshConfig(configYAML, ""); err != nil {
 		csrf := ensureCSRFToken(w, r)
 		data := map[string]interface{}{