Add resumable upload feature with progress display

- Implement chunked file upload with 1MB chunk size
- Add progress bar with percentage and chunk counter (e.g., 2/5)
- Support resuming interrupted uploads
- Improve UI with better progress visualization
- Add dropzone.js integration for drag-and-drop uploads
- Fix progress bar jumping issue in resumable uploads
- Add file type icons and size display
- Enhance error handling and user feedback

static/style.css

@@ -394,13 +394,17 @@ body {
     background: white;
     border-radius: 12px;
     width: 100%;
-    max-width: 450px;
+    max-width: 600px;
     max-height: 90vh;
     overflow: hidden;
     display: flex;
     flex-direction: column;
 }
 
+.upload-modal .modal-content {
+    max-width: 650px;
+}
+
 .modal-large {
     max-width: 900px;
 }
@@ -777,3 +781,177 @@ body {
 .upload-speed.active {
     display: block;
 }
+
+.upload-file-list {
+    margin-top: 15px;
+    max-height: 250px;
+    overflow-y: auto;
+}
+
+.upload-file-item {
+    display: flex;
+    align-items: center;
+    padding: 8px 10px;
+    border: 1px solid #eee;
+    border-radius: 6px;
+    margin-bottom: 6px;
+    background: #fafafa;
+    gap: 10px;
+}
+
+.upload-file-item:last-child {
+    margin-bottom: 0;
+}
+
+.upload-file-item .dz-icon {
+    font-size: 20px;
+    width: 24px;
+    text-align: center;
+    flex-shrink: 0;
+}
+
+.upload-file-item .dz-info {
+    flex: 1;
+    min-width: 0;
+    overflow: hidden;
+}
+
+.upload-file-item .dz-filename {
+    font-size: 12px;
+    color: #333;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    margin-bottom: 2px;
+}
+
+.upload-file-item .dz-size {
+    font-size: 10px;
+    color: #999;
+}
+
+.upload-file-item .dz-progress-wrap {
+    width: 100px;
+    flex-shrink: 0;
+    display: flex;
+    align-items: center;
+}
+
+.upload-file-item .dz-percent {
+    font-size: 11px;
+    color: #666;
+    margin-left: 6px;
+    min-width: 36px;
+    text-align: left;
+    font-family: monospace;
+}
+
+.upload-file-item .dz-chunks {
+    font-size: 10px;
+    color: #999;
+    margin-right: 4px;
+}
+
+.upload-file-item .dz-progress {
+    width: 100%;
+    height: 6px;
+    background: #e0e0e0;
+    border-radius: 3px;
+    overflow: hidden;
+    display: block;
+    margin: 0;
+    padding: 0;
+}
+
+.upload-file-item .dz-upload {
+    display: block;
+    height: 100%;
+    background: #2196f3 !important;
+    border-radius: 3px;
+    width: 0%;
+    transition: width 0.1s linear;
+    min-width: 0;
+}
+
+.upload-file-item .dz-status {
+    width: 24px;
+    text-align: center;
+    font-size: 16px;
+    flex-shrink: 0;
+}
+
+.upload-file-item .dz-success-mark {
+    color: #4caf50;
+    display: none;
+}
+
+.upload-file-item .dz-error-mark {
+    color: #f44336;
+    display: none;
+}
+
+.upload-file-item.dz-success .dz-success-mark {
+    display: inline;
+}
+
+.upload-file-item.dz-error .dz-error-mark {
+    display: inline;
+}
+
+.upload-file-item .dz-remove {
+    color: #999;
+    font-size: 14px;
+    cursor: pointer;
+    padding: 4px 6px;
+    border-radius: 4px;
+    flex-shrink: 0;
+}
+
+.upload-file-item .dz-remove:hover {
+    background: #ffebee;
+    color: #f44336;
+}
+
+.upload-file-item .dz-error-message {
+    color: #f44336;
+    font-size: 11px;
+    padding: 4px 8px;
+    background: #ffebee;
+    border-radius: 4px;
+    margin-top: 4px;
+    display: none;
+}
+
+.upload-file-item.dz-error .dz-error-message {
+    display: block;
+}
+
+.upload-file-item.dz-error .dz-filename {
+    color: #f44336;
+}
+
+.dropzone {
+    border: 2px dashed #e0e0e0 !important;
+    border-radius: 8px !important;
+    background: #fafafa !important;
+    min-height: 100px !important;
+    padding: 20px !important;
+    transition: all 0.2s;
+}
+
+.dropzone:hover,
+.dropzone.dz-drag-hover {
+    border-color: #2196f3 !important;
+    background: #f0f7ff !important;
+}
+
+.dropzone .dz-message {
+    text-align: center;
+    color: #999;
+    font-size: 14px;
+    margin: 20px 0;
+}
+
+.dropzone .dz-preview {
+    display: none !important;
+}