feat(pi-hermes-memory): 接入持久记忆扩展并移除 Hippo

用仓库内 pi-hermes-memory 替换 hippo-memory-pi，清理 Hippo 在组合包中的
全部注入点。

移除 Hippo：
- 删除 hippo-memory-pi/ 与 config/hippo-memory-version。
- extensions/plugin-init.ts 只保留 CodeGraph 初始化目标与预检。
- install.sh / update.sh / uninstall.sh 移除 Hippo CLI 的安装、升级、卸载
  与版本校验逻辑；uninstall.sh 同时删除仅服务于该提示的死代码 ask_yes_no。
- 删除 tests/hippo-extension.test.ts 与 tests/hippo-scripts.test.ts。
- tests/extension-load.test.ts 反转“不得加载 Hermes”的断言为必须加载，
  并断言其排在 pi-compaction 之前。

接入 pi-hermes-memory：
- package.json 增加 file:./pi-hermes-memory 依赖、files 条目与加载入口；
  加载顺序位于 pi-compaction 之前，否则 flushOnCompact 会被 pi-compaction
  的 { cancel: true } 静默跳过。
- 六个记忆工具在 Tool Search 中常驻：memory_search 与 session_search 连同
  context_tree_query 归入 memory-recall，memory_add / memory_replace /
  memory_remove / skill_manage 归入 memory-management。常驻是必需的——注入
  的 memory policy 会在普通工作中指示模型调用它们，schema 不可见会让模型
  静默放弃而不是去 tool_search，同时常驻也保持请求前缀缓存稳定。
- bundleDefaultsVersion 由 2 升到 3；migrate-tool-search-settings.mjs 新增
  上一版快照到当前版本的迁移路径，仍只迁移完整匹配的默认快照并保留自定义
  配置。
- config/pi-permission-policy.jsonc 为六个工具设置 allow：它们只写扩展自己的
  agent 目录数据、不触碰工作区，且 memory_search 每轮都可能被调用，落入
  默认 ask 会产生每轮 AutoReview 往返。

依赖：
- pi-hermes-memory 的 devDependencies 由上游 ^0.80.2 等范围改为与根包一致的
  精确版本。上游范围与根包 0.84.2 不兼容，会让 npm 在本目录嵌套安装第二套
  Pi runtime（实测 229 MB），违反“不得在组合包内再安装一套 Pi runtime”的
  纪律。
- 根 allowScripts 保持只有 better-sqlite3@12.11.1。hermes 的
  better-sqlite3@13 运行时 dlopen 的是包内 N-API 预编译二进制
  prebuilds/<platform>.node，npm 因 binding.gyp 推断出的 node-gyp rebuild
  无需执行；实测删除 build/ 目录后仍正常工作。

文档：AGENTS.md 与 README.md 改写记忆章节，新增 pi-hermes-memory 开发约定，
替换文末的 Hippo 项目记忆块。

验证：根 12 个测试文件、pi-tool-search 的 typecheck/test/build、
pi-permission-system 的 typecheck/2569 测试、pi-hermes-memory 自带的 59 个
测试文件全部通过；隔离 Pi 环境联合加载无错误并生成 bundleDefaultsVersion 3；
npm install 幂等；迁移 helper 对 v2 快照迁移、对自定义配置保留。

pi-tool-search/README.md

@@ -39,8 +39,8 @@ Run `/tool-search-status` to inspect the current catalog source, pinned count, d
 | `context-knowledge` | Context indexing, searching, and web-doc ingestion |
 | `context-observability` | Context stats, doctor, and Insight |
 | `context-administration` | Context upgrade and destructive purge |
-| `memory-recall` | Official Hippo recall/context/status and condensed-output recovery |
-| `memory-management` | Official Hippo remember/outcome tools |
+| `memory-recall` | Hermes memory/session search and condensed-output recovery |
+| `memory-management` | Hermes memory writes and procedural skill management |
 | `subagents` | Launch agents, collect background results, and steer running agents |
 | `user-interaction` | `ask_user_question` model-initiated TUI/RPC questions |
 | `chrome-navigation` | Chrome bridge setup, tabs, navigation, snapshots/find/inspect, waits, and screenshots |
@@ -48,7 +48,7 @@ Run `/tool-search-status` to inspect the current catalog source, pinned count, d
 | `chrome-debugging` | Chrome page evaluation, console/network diagnostics, response retrieval, and file upload |
 | `mcp-management` | Shared MCP adapter management |
 
-Pinned tools are removed from these dynamic groups at runtime. The defaults pin `codegraph_explore`, `lsp_diagnostics`, and the three high-frequency Context Mode execution tools, so none of them consume dynamic group or tool capacity.
+Pinned tools are removed from these dynamic groups at runtime. The defaults pin `codegraph_explore`, `lsp_diagnostics`, the three high-frequency Context Mode execution tools, and all six Hermes memory tools, so none of them consume dynamic group or tool capacity.
 
 ## Loading and eviction
 
@@ -84,21 +84,27 @@ Pi reads this configuration from `<agent-dir>/settings.json` (normally `~/.pi/ag
       "lsp_diagnostics",
       "ctx_execute",
       "ctx_execute_file",
-      "ctx_batch_execute"
+      "ctx_batch_execute",
+      "memory_search",
+      "session_search",
+      "memory_add",
+      "memory_replace",
+      "memory_remove",
+      "skill_manage"
     ],
     "showToolSearchFooterStatus": false,
     "maxActiveGroups": 5,
     "maxToolsPerGroup": 8,
     "maxDynamicTools": 28,
     "groupOverrides": {},
-    "bundleDefaultsVersion": 2
+    "bundleDefaultsVersion": 3
   }
 }
 ```
 
 | Key | Bundle default | Description |
 |---|---|---|
-| `alwaysEnabled` | CodeGraph explore, LSP diagnostics, Context execution trio | Exact names pinned alongside Pi core tools |
+| `alwaysEnabled` | CodeGraph explore, LSP diagnostics, Context execution trio, all six Hermes memory tools | 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 |