feat: per-app telemetry reset button on app detail page

Adds "Telemetria törlése" button that deletes all telemetry records and
known issues for a specific app. Useful after major app updates when old
data is no longer representative.

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

hub/internal/web/server.go

@@ -140,6 +140,14 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		w.Write(chartJS)
 	case path == "/apps" || path == "/apps/":
 		s.handleApps(w, r)
+	case strings.HasPrefix(path, "/apps/") && strings.HasSuffix(path, "/reset-telemetry"):
+		appName := strings.TrimPrefix(path, "/apps/")
+		appName = strings.TrimSuffix(appName, "/reset-telemetry")
+		if r.Method == http.MethodPost {
+			s.handleResetAppTelemetry(w, r, appName)
+		} else {
+			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		}
 	case strings.HasPrefix(path, "/apps/"):
 		appName := strings.TrimPrefix(path, "/apps/")
 		s.handleAppDetail(w, r, appName)