fix: 修复代码审查进度条逻辑

- 后端: file_start 事件改为在获取信号量之后发送，避免并发时所有文件同时'开始'导致进度瞬间跳到90%
- 前端: 进度追踪改为基于 file_end 事件（完成）而非 file_start（开始），进度条平滑反映实际审查进度

services/review.go

@@ -134,7 +134,7 @@ func GenerateReview(db *sql.DB, repoPath, base, head string, topN, concurrency i
 			sem <- struct{}{}        // acquire slot
 			defer func() { <-sem }() // release slot
 
-			// Send file_start (order doesn't matter, frontend tracks by filename)
+			// Send file_start after acquiring semaphore — this means the file is actually being reviewed now
 			if safeCallback != nil {
 				safeCallback("file_start", map[string]interface{}{
 					"file":  f.Filename,

templates/pages/review.html

@@ -368,9 +368,6 @@
                 },
                 file_start(data) {
                     currentFile = data.file || '';
-                    completedFiles++;
-                    const pct = totalFiles > 0 ? Math.round((completedFiles / totalFiles) * 80 + 10) : 50;
-                    document.getElementById('progress-bar').style.width = pct + '%';
                     document.getElementById('progress-text').textContent = `正在审查: ${currentFile} (${completedFiles}/${totalFiles})`;
 
                     // Initialize file review entry
@@ -389,7 +386,10 @@
                     appendSuggestionCard(data);
                 },
                 file_end(data) {
-                    // File done
+                    completedFiles++;
+                    const pct = totalFiles > 0 ? Math.round((completedFiles / totalFiles) * 80 + 10) : 50;
+                    document.getElementById('progress-bar').style.width = pct + '%';
+                    document.getElementById('progress-text').textContent = `已完成 ${completedFiles}/${totalFiles} 个文件`;
                 },
                 file_summary(data) {
                     if (data.file && fileReviews[data.file]) {