docs: 添加 ToolSearch 设计指南 + 禁用 turn-zero 工具推荐弹窗

- 新增 docs/design/tool-search-design-guide.md，涵盖架构、搜索算法、执行管道、演进历史
- 禁用 getTurnZeroSearchExtraToolsPrefetch，消除用户输入时的频繁弹窗
- inter-turn 发现机制保持不变

Co-Authored-By: glm-5-turbo <zai-org@claude-code-best.win>

src/components/SearchExtraToolsHint.tsx

@@ -0,0 +1,53 @@
+import * as React from 'react';
+import { Box, Text } from '@anthropic/ink';
+import { Select } from './CustomSelect/select.js';
+import { PermissionDialog } from './permissions/PermissionDialog.js';
+
+type SearchExtraToolsHintItem = {
+  name: string;
+  description: string;
+  score: number;
+};
+
+type Props = {
+  tools: SearchExtraToolsHintItem[];
+  onSelect: (toolName: string) => void;
+  onDismiss: () => void;
+};
+
+const AUTO_DISMISS_MS = 30_000;
+
+export function SearchExtraToolsHint({ tools, onSelect, onDismiss }: Props): React.ReactNode {
+  const onSelectRef = React.useRef(onSelect);
+  const onDismissRef = React.useRef(onDismiss);
+  onSelectRef.current = onSelect;
+  onDismissRef.current = onDismiss;
+
+  React.useEffect(() => {
+    const timeoutId = setTimeout(ref => ref.current(), AUTO_DISMISS_MS, onDismissRef);
+    return () => clearTimeout(timeoutId);
+  }, []);
+
+  const options = tools.map(t => ({
+    label: `${t.name} — ${t.description.slice(0, 60)} (score: ${t.score.toFixed(2)})`,
+    value: t.name,
+  }));
+
+  options.push({ label: 'Dismiss', value: '__dismiss__' });
+
+  return (
+    <PermissionDialog title="Tool Recommendation">
+      <Select
+        options={options}
+        onChange={value => {
+          if (value === '__dismiss__') {
+            onDismissRef.current();
+          } else {
+            onDismissRef.current();
+            onSelectRef.current(value);
+          }
+        }}
+      />
+    </PermissionDialog>
+  );
+}