fix(preset): keep the token meter host-plane and name unjoined agents

Moving the agent plane behind presets left two readers on the wrong side of
the host/agent line.

`dsh-token-meter` was disabled on the host and mounted inside each preset's
`compaction` realm, but its three projection units register into the
process-wide `sessionProjections` table. A unit registered from one preset
answers for every session, so whether a `minimal` session showed a context
meter depended on whether some other session had mounted `standard` since
boot, and a process that only ever ran `minimal` showed none. The meter takes
no configuration, keys every fold by Session, and registers no tool or prompt
section, so it returns to the host composition and leaves the presets'
`isolate` map; the realm and `compact-basic` stay, because what a preset
chooses is whether its agent compacts, not whether its tokens are counted.

Nothing named an agent that joined no preset. The join is a scope-parent link,
and without it the tools, prompt-section, and skill views resolve the empty
global layer: the agent publishes, the turn runs, and the model receives
nothing. `AgentPresets` now logs one warning per such agent while a roster is
configured, and the invariant companion fails outright — at
`system-prompt/assemble` rather than at publication, because an unjoined agent
is legal until it addresses a model and `recompose` binds exactly such an
agent. The warning stays advisory: a synchronous `agent/created` throw vetoes
publication, and the ACP bridge, SDK server, and headless bundle all create an
unjoined agent today.

Three limits are recorded rather than fixed: projection key presence is not a
per-session capability signal, a superseded standing generation is never
reclaimed, and a `cordis_mount` temporary plugin belongs to the composition
rather than the session that mounted it.

Fixes #2203

packages/self-modification/tool-cordis/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/self-modification/tool-cordis/README.md
-README.md: f2a65043a1d2f74553e98caf59ed3d38b5a70b7c
-README.zh.md: 66742094992d219ccfbd60b935dcd10e48cb12b8
+README.md: 7c8e2e1301f81c5579e7c2cadaf34d0a97270ba7
+README.zh.md: 2f7e66cd9c79c71373618b397e6841b003033bdd

packages/self-modification/tool-cordis/README.md

@@ -87,3 +87,4 @@ Mounting or unmounting a prompt or tool contribution changes later request prefi
 - **The sandbox is containment for honest code, not a security boundary** — host-realm helpers on the sandbox global are reachable, so mount code can reach Node; load this plugin as deliberately as you would grant a bash tool (see § Trust stance).
 - **The `ctx` façade exposes no `effect()`** — mount code cannot register a bespoke disposer; `on`/`provide`/`tools.register` are the supported cleanup paths.
 - **`vmTimeoutMs` bounds only synchronous evaluation** — an async mount body escapes it; there is no async budget on mount code.
+- **Temporary Plugins belong to the composition, not to the session that mounted one** — the group fiber and the `dyn-N` table are this row's own, so every agent the row covers shares them: registered inside an agent preset's standing mount, one session's mount is visible in another session's tool catalog and `cordis_inspect what:"temporary"`, and the second mount of an id replaces the first. That matched the host-plane row this package started as (one per process); it becomes observable once several sessions run the same preset concurrently. Per-session temporary plugins would need the group and table keyed by the calling agent.

packages/self-modification/tool-cordis/README.zh.md

@@ -87,3 +87,4 @@ Namespace 插件：命名导出 `name`／`inject`／`Config`／`apply`，无默
 - **沙箱只用于约束诚实代码，并非安全边界**：可以访问沙箱全局变量上的 host realm helper，因此挂载代码可以触达 Node；加载该插件时，应当像授予 bash 工具一样慎重（见 § 信任立场）。
 - **`ctx` façade 不公开 `effect()`**：挂载代码无法注册定制 disposer；`on`／`provide`／`tools.register` 是受支持的清理路径。
 - **`vmTimeoutMs` 只限制同步求值**：async 挂载主体可逃出该边界；挂载代码没有 async 预算。
+- **临时 Plugin 属于组装，而不属于挂载它的那个会话**：group fiber 与 `dyn-N` 表是本行自己的，因此本行覆盖的每个 agent 共享它们——注册在某个 agent preset 的常驻挂载里时，一个会话挂载出来的东西会出现在另一个会话的工具目录和 `cordis_inspect what:"temporary"` 里，同一个 id 的第二次挂载会顶掉第一次。这与本包最初作为宿主平面行的语义一致（每进程一份）；只有当多个会话并发运行同一 preset 时才变得可观察。要做到逐会话，需要把 group 与表按调用方 agent 建键。

packages/self-modification/tool-cordis/src/api-catalog.ts

@@ -1212,7 +1212,7 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
     methods: [
       {
         signature: 'presentAs(mode: ToolPresentationMode): () => void',
-        jsDoc: '/**\n * Present this agent\'s tools in `mode` instead of the deployment default.\n *\n * Scoped only, and one declaration per agent: this is how an agent preset\n * composes a Code Mode agent beside native ones in the same process, and a\n * process-global override would be the `mode` config field instead.\n * @param mode - the presentation this agent\'s model sees.\n * @returns the exact disposer that restores the deployment default.\n */',
+        jsDoc: '/**\n * Present the calling scope\'s tools in `mode` instead of the deployment\n * default. Nearest scope on the chain wins, so a preset\'s standing\n * declaration covers every agent joined under it.\n *\n * Scoped only, and one declaration per scope: this is how an agent preset\n * composes Code Mode agents beside native ones in the same process, and a\n * process-global override would be the `mode` config field instead.\n * @param mode - the presentation the covered agents\' models see.\n * @returns the exact disposer that restores the deployment default.\n */',
       },
       {
         signature: 'register(definition: ToolDefinition): () => void',