feat(web): 添加全局 Toast 通知系统和资产预览导航功能

- 新增 ToastProvider 和 useToast hook，支持全局成功/错误/信息提示
- 资产预览增加左右导航按钮、键盘快捷键(方向键)和计数器显示
- 资产库增加图片/视频类型筛选标签页及计数
- 对话列表增加最近对话展示、搜索优化和删除确认
- 消息增加删除确认对话框
- 优化聊天自动滚动行为，仅在用户未手动滚动时跟随新内容
- 新增删除消息 API 端点
- 优化消息历史清理逻辑，过滤错误消息和孤儿 tool 消息
- 添加自定义滚动条样式
- 优化账户参考图显示逻辑，支持本地文件显示
- 修复对话创建流程，直接导航到新创建的对话

web/server/ws/chat.ts

@@ -381,6 +381,48 @@ async function streamOpenAI(
   }
 }
 
+// Clean and validate message history before sending to API
+function sanitizeHistory(messages: DbMessage[]): DbMessage[] {
+  // 1. Filter out error messages stored in DB
+  const cleaned = messages.filter((m) => {
+    if (m.role === 'assistant' && m.content.startsWith('抱歉，出错了：')) return false;
+    return true;
+  });
+
+  // 2. Validate sequence: tool messages must follow assistant with tool_calls
+  const result: DbMessage[] = [];
+  for (let i = 0; i < cleaned.length; i++) {
+    const msg = cleaned[i];
+
+    // Tool message: check if preceding assistant has tool_calls
+    if (msg.role === 'tool') {
+      let hasPrecedingToolCall = false;
+      for (let j = result.length - 1; j >= 0; j--) {
+        const prev = result[j];
+        if (prev.role === 'assistant') {
+          if (prev.tool_calls) {
+            try {
+              const parsed = JSON.parse(prev.tool_calls);
+              const blocks = Array.isArray(parsed) ? parsed : parsed.content_blocks;
+              if (blocks?.some((b: ContentBlock) => b.type === 'tool_use')) {
+                hasPrecedingToolCall = true;
+              }
+            } catch {}
+          }
+          break; // stop at nearest assistant
+        }
+        if (prev.role === 'tool') continue; // skip consecutive tool messages
+        break;
+      }
+      if (!hasPrecedingToolCall) continue; // skip orphan tool message
+    }
+
+    result.push(msg);
+  }
+
+  return result;
+}
+
 async function handleChatMessage(ws: WebSocket, convId: string, content: string) {
   const userMsgId = randomUUID();
   getDb().prepare(
@@ -398,9 +440,10 @@ async function handleChatMessage(ws: WebSocket, convId: string, content: string)
   }
   getDb().prepare('UPDATE conversations SET updated_at = datetime(\'now\') WHERE id = ?').run(convId);
 
-  const history = getDb().prepare(
+  const rawHistory = getDb().prepare(
     'SELECT * FROM messages WHERE conversation_id = ? AND id != ? ORDER BY created_at'
   ).all(convId, userMsgId) as DbMessage[];
+  const history = sanitizeHistory(rawHistory);
 
   ws.send(JSON.stringify({ type: 'status', data: { status: 'thinking' } }));
 
@@ -419,9 +462,7 @@ async function handleChatMessage(ws: WebSocket, convId: string, content: string)
     const errMsg = (err as Error).message;
     console.error('[chat] LLM error:', errMsg);
     const errId = randomUUID();
-    getDb().prepare(
-      'INSERT INTO messages (id, conversation_id, role, content) VALUES (?, ?, ?, ?)'
-    ).run(errId, convId, 'assistant', `抱歉，出错了：${errMsg}`);
+    // Don't store error in DB to avoid polluting history
     ws.send(JSON.stringify({
       type: 'message',
       data: { id: errId, role: 'assistant', content: `抱歉，出错了：${errMsg}` },