feat(debug): add Telemetria teszt section to debug page (v0.28.1)

- New GET /api/debug/telemetry endpoint runs full telemetry pipeline on-demand
- GetTelemetryPreview callback added to DebugCallbacks, wired in main.go
- BuildAppTelemetryForDebug() exported wrapper in report/telemetry.go
- Debug page: new collapsible section with per-app table (memory, CPU, log errors/warnings, issues) and raw JSON viewer
- Available regardless of hub configuration

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

controller/internal/web/handler_debug.go

@@ -15,6 +15,7 @@ import (
 
 	"gitea.dooplex.hu/admin/felhom-controller/internal/backup"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/monitor"
+	"gitea.dooplex.hu/admin/felhom-controller/internal/report"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/system"
 )
@@ -27,6 +28,7 @@ type DebugCallbacks struct {
 	TriggerSetupMode       func() error
 	HubConnectivityTest    func() (statusCode int, latencyMs int64, err error)
 	GiteaConnectivityTest  func() (statusCode int, latencyMs int64, err error)
+	GetTelemetryPreview    func() ([]report.AppTelemetry, error)
 }
 
 // debugPageHandler renders the debug dashboard page.
@@ -80,6 +82,10 @@ func (s *Server) handleDebugAPI(w http.ResponseWriter, r *http.Request) {
 	case subpath == "gitea/test-connectivity" && r.Method == http.MethodPost:
 		s.debugGiteaConnectivity(w, r)
 
+	// Section: Telemetry testing
+	case subpath == "telemetry" && r.Method == http.MethodGet:
+		s.debugTelemetry(w, r)
+
 	// Section 6: Self-update
 	case subpath == "selfupdate/dry-run" && r.Method == http.MethodPost:
 		s.debugSelfUpdateDryRun(w, r)
@@ -538,6 +544,40 @@ func (s *Server) debugGiteaConnectivity(w http.ResponseWriter, r *http.Request)
 		fmt.Sprintf("Gitea elérhető (HTTP %d, %dms)", statusCode, latency), data)
 }
 
+// ── Section: Telemetry testing ───────────────────────────────────────
+
+func (s *Server) debugTelemetry(w http.ResponseWriter, r *http.Request) {
+	if s.debugCallbacks == nil || s.debugCallbacks.GetTelemetryPreview == nil {
+		writeDebugJSON(w, http.StatusNotImplemented, false, "Nem bekötött", nil)
+		return
+	}
+	start := time.Now()
+	telemetry, err := s.debugCallbacks.GetTelemetryPreview()
+	latency := time.Since(start).Milliseconds()
+	if err != nil {
+		writeDebugJSON(w, http.StatusOK, false, err.Error(), map[string]interface{}{"latency_ms": latency})
+		return
+	}
+
+	totalErrors := 0
+	totalWarnings := 0
+	for _, app := range telemetry {
+		totalErrors += app.LogErrors
+		totalWarnings += app.LogWarnings
+	}
+
+	writeDebugJSON(w, http.StatusOK, true,
+		fmt.Sprintf("Telemetria összegyűjtve: %d app, %d hiba, %d figyelmeztetés (%dms)",
+			len(telemetry), totalErrors, totalWarnings, latency),
+		map[string]interface{}{
+			"latency_ms":     latency,
+			"app_count":      len(telemetry),
+			"total_errors":   totalErrors,
+			"total_warnings": totalWarnings,
+			"app_telemetry":  telemetry,
+		})
+}
+
 // ── Section 6: Self-update ──────────────────────────────────────────
 
 func (s *Server) debugSelfUpdateDryRun(w http.ResponseWriter, r *http.Request) {