refactor: 视频提取日志原地更新，复用 logStreamProgress 模式

- 新增 resetVideoProgress/updateVideoProgress/finishVideoProgress
- 日志面板中视频提取只占一条，实时更新帧数和状态
- 主进程只通过 video:progress IPC 推送原始帧数，不写日志

src/renderer/services/log-service.ts

@@ -187,7 +187,6 @@ export function resetStreamProgress(): void {
 
 /** 更新**最新**一条流式进度日志（原地更新消息，不改变 DOM 位置和时间戳） */
 export function logStreamProgress(msg: string): void {
-  // 找最后一条进度日志（当前轮）
   const all = logBodyEl?.querySelectorAll?.('.log-stream-progress');
   if (all && all.length > 0) {
     const latest = all[all.length - 1] as HTMLElement;
@@ -196,6 +195,40 @@ export function logStreamProgress(msg: string): void {
   }
 }
 
+/** 视频提取进度：创建初始条目 */
+export function resetVideoProgress(fileName: string): void {
+  if (!logBodyEl) return;
+  const entry = document.createElement('div');
+  entry.className = 'log-entry log-info log-video-progress';
+  entry.innerHTML = `<span class="log-time">${formatTime(Date.now())}</span><span class="log-icon">🎬</span><span class="log-msg">开始提取视频帧: ${escapeHtml(fileName)}</span><pre class="log-detail">0 帧</pre>`;
+  logBodyEl.appendChild(entry);
+}
+
+/** 更新视频提取进度（原地更新，不新增条目） */
+export function updateVideoProgress(current: number): void {
+  const all = logBodyEl?.querySelectorAll?.('.log-video-progress');
+  if (all && all.length > 0) {
+    const latest = all[all.length - 1] as HTMLElement;
+    const detail = latest.querySelector('.log-detail');
+    if (detail) detail.textContent = `${current} 帧`;
+  }
+}
+
+/** 视频提取完成：将进度条目原地更新为完成状态 */
+export function finishVideoProgress(fileName: string, frameCount: number, duration: number): void {
+  const all = logBodyEl?.querySelectorAll?.('.log-video-progress');
+  if (all && all.length > 0) {
+    const latest = all[all.length - 1] as HTMLElement;
+    latest.className = 'log-entry log-success';
+    const icon = latest.querySelector('.log-icon');
+    const msg = latest.querySelector('.log-msg');
+    const detail = latest.querySelector('.log-detail');
+    if (icon) icon.textContent = '✅';
+    if (msg) msg.textContent = `视频帧提取完成: ${escapeHtml(fileName)}`;
+    if (detail) detail.textContent = `${frameCount} 帧 / ${duration.toFixed(1)}s (1fps)`;
+  }
+}
+
 export function logAgentLoop(iteration: number, maxLoops: number): void { addLog('info', `Loop #${iteration}/${maxLoops}`); }
 export function logModelResponse(contentLen: number, toolCalls: number): void { addLog('stream', `响应: ${contentLen}字, ${toolCalls}工具`); }
 export function logConnection(status: string, detail?: string): void { addLog(status === 'connected' ? 'success' : 'warn', `连接: ${status}`, detail); }