feat(prompt): 搜索引导改为意图→工具的正向指引，multi_grep 按上游保持关闭

真实会话中模型仍用 bash grep -o | sort -u 做抽取，被拒后直接放弃核对；
原提示词只说"不要"，没告诉它抽取/计数、给程序传文件清单、过滤命令输出时该用什么。

- routing：按已知信息选 grep/find（多变体用 grep 正则 alternation），
  codemode + tools.grep 做聚合，bash 文件清单用 git ls-files，
  overflow_query 过滤输出，被拒后改用替代方案继续
- 权限策略：rg/grep/git grep/find/fd 的 deny 附带指向替代工具的 reason
- tools.jsonc：grep/find 新 snippet，补上 codegraph_explore snippet
- FFF 上游标注 multi_grep 有害：wrapper 删除 PI_FFF_MULTIGREP，清理全部引用
- JSONC 测试改用字符串感知的注释剥离（reason 中含 'src/**/*.ts'）

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

pi-tool-search/extensions/bundle-groups.ts

@@ -25,11 +25,11 @@ export const BUNDLE_GROUP_DEFINITIONS: BundleGroupDefinition[] = [
   {
     id: "filesystem-navigation",
     title: "Filesystem navigation",
-    summary: "Inspect directory layouts and run bounded multi-pattern literal searches.",
-    useWhen: ["You need directory entries or several literal searches after narrowing a path"],
+    summary: "Inspect directory layouts.",
+    useWhen: ["You need the alphabetical directory entries of an unknown path"],
     avoidWhen: ["Code relationships or types are the real question"],
-    keywords: ["files", "directory", "list", "multi grep", "目录", "文件", "多模式搜索"],
-    tools: ["ls", "multi_grep"],
+    keywords: ["files", "directory", "list", "目录", "文件"],
+    tools: ["ls"],
   },
   {
     id: "ssh-connection",