✨ feat(ai-chat): 全面升级AI聊天面板并优化交互体验

- 消息管理：新增聊天气泡的重试、编辑与单条删除功能及相对应的持久化状态函数
- 快捷操作：支持长文一键滑动到底端，并在代码块内增加SQL一键送入编辑器的快捷执行机制
- 视觉优化：深化AI回复背景沉浸感，重绘AI洞察按钮并移除设置面板所有的冗余紫色调
- 设置调优：放宽模型初始必填限制，新增内置系统提示词（Builtin Prompt）全览面板

frontend/src/components/TableOverview.tsx

@@ -138,6 +138,7 @@ const TableOverview: React.FC<TableOverviewProps> = ({ tab }) => {
     const connections = useStore(state => state.connections);
     const theme = useStore(state => state.theme);
     const addTab = useStore(state => state.addTab);
+    const setActiveContext = useStore(state => state.setActiveContext);
     const darkMode = theme === 'dark';
 
     const [tables, setTables] = useState<TableStatRow[]>([]);
@@ -195,6 +196,7 @@ const TableOverview: React.FC<TableOverviewProps> = ({ tab }) => {
 
     const openTable = useCallback((tableName: string) => {
         if (!connection) return;
+        setActiveContext({ connectionId: connection.id, dbName: tab.dbName || '' });
         addTab({
             id: `${connection.id}-${tab.dbName}-${tableName}`,
             title: tableName,
@@ -203,10 +205,11 @@ const TableOverview: React.FC<TableOverviewProps> = ({ tab }) => {
             dbName: tab.dbName,
             tableName,
         });
-    }, [connection, tab.dbName, addTab]);
+    }, [connection, tab.dbName, addTab, setActiveContext]);
 
     const openDesign = useCallback((tableName: string) => {
         if (!connection) return;
+        setActiveContext({ connectionId: connection.id, dbName: tab.dbName || '' });
         addTab({
             id: `design-${connection.id}-${tab.dbName}-${tableName}`,
             title: `设计表 (${tableName})`,
@@ -217,7 +220,7 @@ const TableOverview: React.FC<TableOverviewProps> = ({ tab }) => {
             initialTab: 'columns',
             readOnly: false,
         });
-    }, [connection, tab.dbName, addTab]);
+    }, [connection, tab.dbName, addTab, setActiveContext]);
 
     const buildConfig = useCallback(() => {
         if (!connection) return null;
@@ -383,6 +386,7 @@ const TableOverview: React.FC<TableOverviewProps> = ({ tab }) => {
                                 menu={{
                                     items: [
                                         { key: 'new-query', label: '新建查询', icon: <ConsoleSqlOutlined />, onClick: () => {
+                                            setActiveContext({ connectionId: tab.connectionId, dbName: tab.dbName || '' });
                                             addTab({
                                                 id: `query-${Date.now()}`,
                                                 title: '新建查询',