fix(plugins): 内置清单终审 15 → 13 —— kbtree/multimodal 翻案加回

## 翻案依据（逐方法对照公开 SDK，非方法名 grep）

初判把 kbtree/multimodal 归入"只用公开 SDK"，错了。两边的
s.Knowledge() / s.LLM() **同名但接口面不同**：

- kbtree 需要 KnowledgeAPI.Subtree/CategoryCounts/SearchIn/Categories
  与 KnowledgeTreeView/KnowledgeCategoryCount 类型 —— 公开 KnowledgeAPI
  只有 Search/Add/List，树视图类型公开面根本没有
- multimodal 需要 LLMAPI.Chat + LLMMessage/LLMContentBlock ——
  公开 LLMAPI 只有 ListSources/SetSource/CurrentSource，没有 Chat

外置它们 = OCR/看图/转写、知识树浏览静默失效。

## 最终内置 13 个

  cli webui agentcli healthcheck pluginmgr seq remotedevice
  clawhubadapter kbtree multimodal cfgmgr skillmgr seemedia

外置 5 个（SDK 仓 example/ 已提供工程并已部署验证）：
  cmd localuse mcp（本轮）+ ai_image files（此前）+ timer（更早）

## 文档同步（中英 6 份）

数量 11 → 13；判定标准小节补「终审翻案」与教训：
**判外置与否必须逐方法对照公开接口，同名方法不等于同面。**

验证：go build/vet/test 全绿；生产实例已部署新内核 + 新插件包，
四个按需插件经 plugin_start 拉起、工具全部注册（cmd_run /
local_screensee / mcp_* / files_edit_line 实核）。

assets/docs/en/ARCHITECTURE.md

@@ -318,7 +318,7 @@ VM built-ins: `json.encode` / `json.decode` / `log` / `http_get` / `http_post`.
 
 | Method | Registration Mechanism | Compilation | Usage |
 |--------|----------------------|-------------|-------|
-| Built-in | `init()` → `RegisterFactory` | `internal/plugins/` compiled into kernel | webui/cli/agentcli etc. (11 total; see the criteria section below) |
+| Built-in | `init()` → `RegisterFactory` | `internal/plugins/` compiled into kernel | webui/cli/agentcli etc. (13 total; see the criteria section below) |
 | External subprocess plugin | Handshake + stdio JSON-RPC reverse registration | `hmapdev build` → `plugin.bin` (ordinary Go binary) | qq/browser/files etc. |
 | Lua script plugin | Execute `main.lua` to register tools | No compilation, takes effect after restart/reload | luademo etc. |
 | SKILL plugin | Parse `SKILL.md` | Markdown definition | Loaded via clawhubadapter |
@@ -372,7 +372,19 @@ Counter-examples (externalized, because public capabilities suffice):
 | Plugin | Actual dependencies |
 |---|---|
 | timer | RegisterTool + Settings + InjectText (public) |
-| ai_image / files / cmd / kbtree / localuse / mcp / multimodal | RegisterTool + Settings (+ public APIs such as s.Knowledge()) |
+| ai_image / files / cmd / localuse / mcp | RegisterTool + Settings (+ public RegisterStage) |
+
+> ★ Reversal on final review (2026-10-19, method-by-method comparison against
+> the public SDK brought two back): **kbtree** needs
+> `KnowledgeAPI.Subtree/CategoryCounts/SearchIn/Categories` — the public
+> `KnowledgeAPI` only has `Search/Add/List`, and the public SDK lacks the
+> `KnowledgeTreeView`/`KnowledgeCategoryCount` types. **multimodal** needs
+> `LLMAPI.Chat` + `LLMMessage`/`LLMContentBlock` — the public `LLMAPI` only
+> has `ListSources/SetSource/CurrentSource`. Both were initially misjudged as
+> "public-only" because `s.Knowledge()`/`s.LLM()` exist on both sides **with
+> the same names but different surfaces**. Lesson: externalization decisions
+> require method-by-method comparison against the public interface, not name
+> matching.
 
 > ⚠️ Both copies existing at once is forbidden: `loadOne` checks the built-in
 > factory table first and never looks at the external `plugin.bin` if it hits
@@ -641,7 +653,7 @@ internal/
 │   ├── registry.go        — Registry + lifecycle
 │   ├── dynamic.go         — Load-channel dispatch (proc / lua / skill); .so only remains to error loudly
 │   └── manifest.go        — plugin.json metadata
-├── plugins/               — Built-in plugin implementations (11; see "Which Plugins Stay Built-in")
+├── plugins/               — Built-in plugin implementations (13; see "Which Plugins Stay Built-in")
 │   ├── all.go             — Blank imports (**the single authoritative list**; edit only this)
 │   ├── webui/             — HTTP server + embedded SPA
 │   ├── cli/               — Unix socket CLI
@@ -655,7 +667,7 @@ internal/
 │   ├── seemedia/          — Direct media view
 │   ├── seq/               — Sequence orchestration
 │   ├── data/ plugin_data/ — Plugin static assets (non-Go, shipped with the kernel)
-│   ├── kbtree/ cmd/ localuse/ mcp/ multimodal/ ai_image/ files/
+│   ├── cmd/ localuse/ mcp/ ai_image/ files/
 │   │                      — Source remains but **not listed in all.go**: externalized
 │   │                        on 2026-10-19 as .hmap packages (projects in the SDK repo's
 │   │                        example/); directories to be removed once external projects stabilize