feat: 调度器+并发管线+GPU优化+日志分级+前端修复

- scheduler: ffmpeg 异步线程 + GPU 串行调度 + 模型复用（2N→2 次加载）
- pipeline: 阶段拆分（extract/asr/translate），中间数据存 Task 字段
- translate_service: 长度排序批处理，padding 浪费减少 91%
- model_manager: ASR/翻译不共驻，BatchedInferencePipeline 批量解码
- 日志分级: INFO=任务流转里程碑，DEBUG=进度详情；默认 INFO
- 前端: 日志最新在上+滚动感知+退避轮询；24h 时间；上传中状态显示
- /health: 返回完整 Whisper/NLLB 配置
- upload_service: 单事务 complete + 扩展名白名单
- task_router: 合并 UploadSession 虚拟任务到列表
- Dockerfile: CPU/GPU 独立构建链，deps 缓存稳定
- prefetch_models: 安装时预下载模型权重

app/views/history_html.py

@@ -68,7 +68,11 @@ function renderTable(tasks) {{
     const tr = document.createElement("tr");
     const label = STATUS_LABEL[task.status] || task.status;
     const stateClass = "st-" + (task.status === "done" ? "done" : task.status === "failed" ? "fail" : "running");
-    const created = new Date(task.created_at).toLocaleString();
+    let created;
+    try {{ created = fmtDateTime24(new Date(task.created_at + "Z")); }}
+    catch (e) {{ created = task.created_at; }}
+
+    let idDisplay = task.is_upload ? "—" : "#" + task.id;
 
     let action;
     if (task.status === "done") {{
@@ -84,10 +88,13 @@ function renderTable(tasks) {{
     let progress;
     if (task.status === "done") progress = "100%";
     else if (task.status === "failed") progress = "—";
-    else progress = `<div class="mini-bar"><div class="mini-fill" style="width:${{task.progress}}%"></div></div>${{task.progress.toFixed(0)}}%`;
+    else {{
+      const pct = (task.progress == null) ? 0 : task.progress;
+      progress = `<div class="mini-bar"><div class="mini-fill" style="width:${{pct}}%"></div></div>${{pct.toFixed(0)}}%`;
+    }}
 
     tr.innerHTML = `
-      <td class="muted">#${{task.id}}</td>
+      <td class="muted">${{idDisplay}}</td>
       <td>${{escapeHtml(task.filename)}}</td>
       <td><span class="status-tag ${{stateClass}}">${{label}}</span></td>
       <td>${{progress}}</td>