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/docs/dynamic-tool-loading.md

@@ -2,7 +2,7 @@
 
 `pi-tool-search` keeps full low-frequency schemas hidden behind a compact, validated group catalog.
 
-1. `session_start` activates `tool_search`, the six cross-platform Pi core tools, and configured `alwaysEnabled` names. The my-pi defaults also pin CodeGraph exploration, LSP diagnostics, and the three high-frequency Context Mode execution tools. On Windows, `powershell` is pinned beside `bash`; on non-Windows hosts it is excluded. Pinned tools do not consume the dynamic-group or dynamic-tool budget.
+1. `session_start` activates `tool_search`, the six cross-platform Pi core tools, and configured `alwaysEnabled` names. The my-pi defaults also pin CodeGraph exploration, LSP diagnostics, the three high-frequency Context Mode execution tools, and the six Hermes memory tools. On Windows, `powershell` is pinned beside `bash`; on non-Windows hosts it is excluded. Pinned tools do not consume the dynamic-group or dynamic-tool budget.
 2. Hidden definitions are hashed with grouping constraints and matched against `extensions/bundle-groups.ts`. Available standard tools receive checked-in groups; unavailable optional tools are omitted.
 3. If every hidden tool is recognized, the bundle catalog is used directly. No model call or per-user cache is required.
 4. Additional tools receive immediate deterministic prefix/source groups. A matching model-enriched cache is reused only if it preserves all checked-in bundle assignments.
@@ -13,7 +13,7 @@
 9. Natural-language lookup gives exact tool names and workflow aliases more weight than descriptive overlap. Weak or closely tied matches return candidates without activation.
 10. `turn_start` notices tool or grouping-configuration changes by hash, resets stale dynamic groups, and reconstructs the checked-in/hybrid catalog.
 
-The standard bundle assigns the official Hippo Pi extension's five `hippo_*` tools to recall and management groups, and assigns `Agent`, `get_subagent_result`, and `steer_subagent` to the `subagents` orchestration group. `context_tree_query` remains in `memory-recall` because it recovers condensed tool output; retired Hermes names and third-party `tff-memory_*` names are not seeded.
+The standard bundle assigns the Hermes memory extension's six tools to recall and management groups: `memory_search` and `session_search` join `context_tree_query` in `memory-recall`, while `memory_add`, `memory_replace`, `memory_remove`, and `skill_manage` form `memory-management`. All six are pinned by default, because the injected `<memory-policy>` tells the model to consult and write memory during normal work, and a schema the model cannot see would silently disable that loop. Third-party `tff-memory_*` names and the retired Hippo `hippo_*` names are not seeded. It also assigns `Agent`, `get_subagent_result`, and `steer_subagent` to the `subagents` orchestration group.
 The maintained `pi-ssh` tools are also split by workflow: sequential reviewed agent-controlled connection lives in `ssh-connection`, structured `ssh_read`/`ssh_write`/`ssh_edit` file operations live in `ssh-remote-files`, bounded `ssh_find`/`ssh_grep` discovery lives in `ssh-remote-search`, and sequential reviewed workspace changes plus reviewed command execution live in `ssh-remote-shell`. The workflows tell the model to call `ssh_connect` or `ssh_cd` separately and wait for success before issuing remote calls that depend on the new connection or cwd.
 The maintained `ask_user_question` tool has its own `user-interaction` group so the model can load the complete interactive schema only when a missing decision or preference must come from the user.
 The pinned `pi-chrome` bridge registers its 21 `chrome_*` tools only after explicit per-session authorization. Once registered, catalog refresh assigns them to `chrome-navigation`, `chrome-interaction`, and `chrome-debugging`; the 28-tool default allows all three groups to coexist. Revocation remains enforced inside every upstream tool execution even if a schema is later reactivated by Tool Search.