fix: 独立图片在视频帧之前描述，明确 images 数组索引边界

- 图片: images[0] 请单独分析
- 视频帧: images[1..30] 为帧序列
- 避免模型把独立图片混入视频帧

src/renderer/components/input-area.ts

@@ -1013,6 +1013,13 @@ async function sendMessageWithAgentLoop(text: string, currentSession: ChatSessio
       apiParts.push(...fileParts);
       logInfo('📄 文件内容已注入', `${fileParts.length} 段, 共 ${fileContents.reduce((s, f) => s + f.content.length, 0)} 字符`);
     }
+    // 独立图片（与 images 数组前 N 张对应，在视频帧之前描述）
+    if (pendingImages.length === 1) {
+      apiParts.push(`[独立图片: ${pendingImages[0].name}]（images[0]，请单独分析）`);
+    } else if (pendingImages.length > 1) {
+      const imgNames = pendingImages.map(img => img.name).join(', ');
+      apiParts.push(`[${pendingImages.length} 张独立图片: ${imgNames}]（images[0..${pendingImages.length - 1}]，请分别分析）`);
+    }
     let allVids: Array<{ name: string; count: number; dur: number; frames: Array<{ timestampSeconds: number; name: string }> }> = [];
     if (hasVideos) {
       if (pendingVideoMeta && pendingVideoFrames.length > 0) {
@@ -1026,12 +1033,11 @@ async function sendMessageWithAgentLoop(text: string, currentSession: ChatSessio
         const fl = v.frames.map(f => `  ${String(f.timestampSeconds).padStart(4, ' ')}s — ${f.name}`).join('\n');
         parts.push(`[视频帧序列 · ${v.name} · ${v.count}帧 · 1fps · ${v.dur.toFixed(0)}s]\n${fl}`);
       }
+      const offset = pendingImages.length;
+      apiParts.push(`以下 images[${offset}..${offset + allVids.reduce((s, v) => s + v.count, 0) - 1}] 为视频帧序列：`);
       apiParts.push(parts.join('\n\n'));
       apiParts.push('上述帧按时间顺序排列，帧间存在时序关系。请分析视频内容。');
     }
-    if (pendingImages.length > 0) {
-      apiParts.push(pendingImages.length === 1 ? `[同时上传了图片: ${pendingImages[0].name}]` : `[同时上传了 ${pendingImages.length} 张图片]`);
-    }
     apiContentForModel = apiParts.join('\n\n');
 
     const msg: ChatMessage = {