fix: multiple improvements and CI/CD updates

Frontend fixes:
- Add missing translations for chunk upload (upload.uploadingChunks, common.chunk)
- Fix photo deletion visual bug by tracking deletion state per photo
- Prevent UI confusion when deleting photos in admin grid

Backend fixes:
- Add file existence checks before deleting thumbnails
- Prevent ENOENT errors for missing thumbnail files
- Improve error handling in photo deletion

CI/CD updates:
- Remove Gitea release creation from Drone pipeline
- Simplify GitHub mirror workflow (remove history rewriting, keep file removal)
- Add clean-git-history.sh script for manual history cleanup

These changes improve the admin photo management experience and streamline
the CI/CD process for better maintainability.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

frontend/src/components/admin/AdminPhotoGrid.tsx

@@ -23,7 +23,7 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
   const [selectedPhotos, setSelectedPhotos] = useState<Set<number>>(new Set());
   const [isSelectionMode, setIsSelectionMode] = useState(false);
   const [isDeleting, setIsDeleting] = useState(false);
-  const [deletingPhotoId, setDeletingPhotoId] = useState<number | null>(null);
+  const [deletingPhotos, setDeletingPhotos] = useState<Set<number>>(new Set());
 
   const handlePhotoSelect = (photoId: number, e?: React.MouseEvent) => {
     if (e) {
@@ -54,15 +54,18 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
       return;
     }
 
-    setDeletingPhotoId(photo.id);
+    setDeletingPhotos(prev => new Set(prev).add(photo.id));
     try {
       await photosService.deletePhoto(eventId, photo.id);
       toast.success('Photo deleted successfully');
       onPhotosDeleted();
     } catch (error) {
       toast.error('Failed to delete photo');
-    } finally {
-      setDeletingPhotoId(null);
+      setDeletingPhotos(prev => {
+        const newSet = new Set(prev);
+        newSet.delete(photo.id);
+        return newSet;
+      });
     }
   };
 
@@ -75,14 +78,18 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
     }
 
     setIsDeleting(true);
+    const selectedIds = Array.from(selectedPhotos);
+    setDeletingPhotos(new Set(selectedIds));
+    
     try {
-      await photosService.deletePhotos(eventId, Array.from(selectedPhotos));
+      await photosService.deletePhotos(eventId, selectedIds);
       toast.success(`${count} photo${count > 1 ? 's' : ''} deleted successfully`);
       setSelectedPhotos(new Set());
       setIsSelectionMode(false);
       onPhotosDeleted();
     } catch (error) {
       toast.error('Failed to delete photos');
+      setDeletingPhotos(new Set());
     } finally {
       setIsDeleting(false);
     }
@@ -155,13 +162,15 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
 
       {/* Photo Grid */}
       <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 xl:grid-cols-5 gap-4">
-        {photos.map((photo, index) => (
-          <div
-            key={photo.id}
-            className={`relative group cursor-pointer rounded-lg overflow-hidden bg-neutral-100 ${
-              isSelectionMode ? 'ring-2 ring-offset-2 ' + (selectedPhotos.has(photo.id) ? 'ring-primary-500' : 'ring-transparent') : ''
-            }`}
-            onClick={() => isSelectionMode ? handlePhotoSelect(photo.id) : onPhotoClick(photo, index)}
+        {photos.map((photo, index) => {
+          const isDeleting = deletingPhotos.has(photo.id);
+          return (
+            <div
+              key={photo.id}
+              className={`relative group cursor-pointer rounded-lg overflow-hidden bg-neutral-100 transition-opacity ${
+                isSelectionMode ? 'ring-2 ring-offset-2 ' + (selectedPhotos.has(photo.id) ? 'ring-primary-500' : 'ring-transparent') : ''
+              } ${isDeleting ? 'opacity-50' : ''}`}
+              onClick={() => !isDeleting && (isSelectionMode ? handlePhotoSelect(photo.id) : onPhotoClick(photo, index))}
           >
             {/* Selection Checkbox */}
             {isSelectionMode && (
@@ -219,8 +228,8 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
                     </button>
                     <button
                       onClick={(e) => handleDeleteSingle(photo, e)}
-                      className="p-1 text-white hover:bg-white/20 rounded"
-                      disabled={deletingPhotoId === photo.id}
+                      className="p-1 text-white hover:bg-white/20 rounded disabled:opacity-50"
+                      disabled={isDeleting}
                     >
                       <Trash2 className="w-3 h-3" />
                     </button>
@@ -238,7 +247,8 @@ export const AdminPhotoGrid: React.FC<AdminPhotoGridProps> = ({
               </div>
             )}
           </div>
-        ))}
+          );
+        })}
       </div>
 
       {photos.length === 0 && (

frontend/src/components/admin/PhotoUpload.tsx

@@ -256,7 +256,7 @@ export const PhotoUpload: React.FC<PhotoUploadProps> = ({ eventId, onUploadCompl
           <div className="flex justify-between text-sm text-neutral-600 mb-1">
             <span>
               {t('upload.uploading')}
-              {totalChunks > 1 && ` (${t('common.chunk') || 'Chunk'} ${currentChunk}/${totalChunks})`}
+              {totalChunks > 1 && ` (${t('common.chunk')} ${currentChunk}/${totalChunks})`}
             </span>
             <span>{uploadProgress}%</span>
           </div>
@@ -268,7 +268,7 @@ export const PhotoUpload: React.FC<PhotoUploadProps> = ({ eventId, onUploadCompl
           </div>
           {totalChunks > 1 && (
             <p className="text-xs text-neutral-500 mt-1">
-              {t('upload.uploadingChunks') || `Uploading ${selectedFiles.length} files in ${totalChunks} batches...`}
+              {t('upload.uploadingChunks', { count: selectedFiles.length, total: totalChunks })}
             </p>
           )}
         </div>

frontend/src/i18n/locales/de.json

@@ -35,7 +35,8 @@
     "days": "Tage",
     "customize": "Anpassen",
     "hide": "Ausblenden",
-    "unknown": "Unbekannt"
+    "unknown": "Unbekannt",
+    "chunk": "Teil"
   },
   "upload": {
     "photoCategory": "Fotokategorie",
@@ -51,7 +52,8 @@
     "uploadPhotos": "Fotos hochladen",
     "maxFilesReached": "Maximal 500 Dateien erlaubt",
     "someFilesSkipped": "Einige Dateien wurden übersprungen (500 Dateien Limit)",
-    "tooManyFiles": "Maximal 500 Dateien können gleichzeitig hochgeladen werden"
+    "tooManyFiles": "Maximal 500 Dateien können gleichzeitig hochgeladen werden",
+    "uploadingChunks": "Lade {{count}} Dateien in {{total}} Teilen hoch..."
   },
   "navigation": {
     "dashboard": "Dashboard",

frontend/src/i18n/locales/en.json

@@ -35,7 +35,8 @@
     "days": "days",
     "customize": "Customize",
     "hide": "Hide",
-    "unknown": "Unknown"
+    "unknown": "Unknown",
+    "chunk": "Chunk"
   },
   "upload": {
     "photoCategory": "Photo Category",
@@ -51,7 +52,8 @@
     "uploadPhotos": "Upload Photos",
     "maxFilesReached": "Maximum 500 files allowed",
     "someFilesSkipped": "Some files were skipped (500 file limit)",
-    "tooManyFiles": "Maximum 500 files can be uploaded at once"
+    "tooManyFiles": "Maximum 500 files can be uploaded at once",
+    "uploadingChunks": "Uploading {{count}} files in {{total}} batches..."
   },
   "navigation": {
     "dashboard": "Dashboard",