feat: add sticky progress bar for batch operations

批量下载、批量取消和批量删除操作添加固定在顶部的进度条。
使用 CSS sticky-top 确保进度条始终可见，无论滚动位置如何。

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

web/src/work/view/parseModal.ts

@@ -77,9 +77,9 @@ export class ParseModalComp implements VanComponent {
                         div({ class: `h5 modal-title` }, () => this.isDownloading.val ? '正在创建下载任务...' : (allFinish.val ? '批量下载' : '批量解析')),
                         button({ class: `btn-close`, 'data-bs-dismiss': `modal` })
                     ),
+                    // 进度条固定在头部下方
+                    this.StickyProgress(),
                     div({ class: `modal-body vstack gap-3`, tabIndex: -1, style: 'outline: none;' },
-                        this.ParseProgress(),
-                        this.DownloadProgress(),
                         div({ class: 'vstack gap-2', hidden: () => this.errorList.val.length == 0 || !allFinish.val || this.isDownloading.val },
                             div({ class: 'text-danger' }, () => `以下 ${this.errorList.val.length} 个视频解析失败`),
                             () => div({ class: 'list-group' },
@@ -218,6 +218,18 @@ export class ParseModalComp implements VanComponent {
         )
     }
 
+    /** 固定在顶部的进度条 */
+    StickyProgress() {
+        return div({
+            class: 'sticky-top bg-body p-3 border-bottom',
+            hidden: () => this.totalCount.val == this.finishCount.val && !this.isDownloading.val,
+            style: 'z-index: 10;'
+        },
+            this.ParseProgress(),
+            this.DownloadProgress(),
+        )
+    }
+
     DownloadProgress() {
         return div({ class: 'vstack gap-3', hidden: () => !this.isDownloading.val },
             div({ class: 'text-center fs-5' }, () => `正在创建下载任务 (${this.downloadProgress.val}/${this.downloadTotal.val})`),