feat(pi-overflow): 新增统一的新工具结果展示截断扩展

此前截断分散在多层且互相冲突：Pi bash 保留尾部 50KB，RTK 兜底截断又只留
开头 12000 字符（砍掉报错与完整输出路径），pi-chrome 截开头 30K，web_fetch
各 provider 不一致。新扩展统一负责"新结果给模型看多少"：
- capture.ts 最先加载暂存原文，index.ts 最后加载（system-prompt 之前）
- 超过 24K 字符时原文落盘 <agentDir>/my-pi/pi-overflow/（700/600、原子写），
  优先取 bash fullOutputPath 完整文件；模型看到 头 + 中段信号行 + 尾 的有界
  视图，行号基于落盘原文、结尾永远可见
- overflow_query：按 id 正则搜索、行区间、jsonPath 只读查询，id 校验防穿越
- 收编：RTK truncate 默认关闭、删除 pi-chrome truncateText、web_fetch 默认
  每页 20000（上限 100000）、web_search max_results 限定 1–20
- pi-compaction 遮蔽带 details.overflow.id 的结果时在占位符提示 overflow_query
- 登记 tools.jsonc / routing / 权限 allow / tool-search 常驻与分组

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

pi-tool-search/README.md

@@ -87,7 +87,8 @@ Pi reads this configuration directly from the installed bundle's `config/tool-se
     "memory_replace",
     "memory_remove",
     "skill_manage",
-    "context_tree_query"
+    "context_tree_query",
+    "overflow_query"
   ],
   "showToolSearchFooterStatus": false,
   "maxActiveGroups": 5,
@@ -99,7 +100,7 @@ Pi reads this configuration directly from the installed bundle's `config/tool-se
 
 | Key | Bundle default | Description |
 |---|---|---|
-| `alwaysEnabled` | CodeGraph explore, LSP diagnostics, Context execution trio, all six Hermes memory tools, `context_tree_query` | Exact names pinned alongside Pi core tools |
+| `alwaysEnabled` | CodeGraph explore, LSP diagnostics, Context execution trio, all six Hermes memory tools, `context_tree_query`, `overflow_query` | Exact names pinned alongside Pi core tools |
 | `showToolSearchFooterStatus` | `false` | Show active tool/group counts |
 | `maxActiveGroups` | `5` | Maximum simultaneously active dynamic groups |
 | `maxToolsPerGroup` | `8` | Maximum size accepted from model-generated groups |