fix(agent-presets,web): broken presets are roster rows, not gaps

A hand-damaged preset was silent until the worst moment. An unparsable
composition listed as an ordinary selectable row and failed only at the
next session start — set as default, every new session failed. A
directory whose composition file was deleted vanished from the roster
while still occupying its id: copy answered "delete the existing preset
first" while remove answered "not found", a dead end.

Discovery now owns health: every id-shaped directory is a roster slot,
broken when its composition is missing or unloadable, checked with the
loader's own entryListSchema dialect (!!js included) so health never
rejects what the loader accepts. `broken` rides AgentPreset, the
agentPreset.list entry, and the UI row; mount/recompose/standingKeyFor
refuse broken up front with the discovery-reported reason, while
resolve/read/remove still answer. The section renders marked red cards —
unselectable, uncopyable, deletable, location kept on custom rows — and
both pickers drop broken rows entirely.

The cordis preset's persona now forbids editing the shipped install
(corrupting cordis would disable the mode itself) and points authoring
at $DSH_HOME/.agent-presets; its skill teaches preset.yml metadata, the
copy-first workflow, the one-escalation sandbox reality, and honest
verification. Exercised live: asked to edit the shipped composition the
composed agent refuses citing both rules; asked for real presets (simple
and complex) it lands them under the user root with one approved
escalation each and self-checks with the loader dialect.

packages/host/apiproxy/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/host/apiproxy/README.md
-README.md: c54c90e0ef243dd1910a4b34a2adf05dd8d43b66
-README.zh.md: 4965eb3375090c7ffafab536feee03e8015504c0
+README.md: 5567a1f0c9a428b9f5168707afd76fb534a30736
+README.zh.md: 87a98a9af21c351f2b5a4003b480b5e46a4e41e8

packages/host/apiproxy/README.md

@@ -46,7 +46,7 @@ Directory picking delegates to the composed `ctx.directoryPicker` backend ([the
 
 `host.openPath` opens a filesystem path with the operating system's default application (`open` on macOS, `Invoke-Item` on Windows, and `xdg-open` on desktop Linux). For `.html`, `.htm`, `.xhtml`, and `.svg`, macOS and desktop Linux prefer a named default browser and fall back to that application handoff when none can be named. WSL translates every Linux path through `wslpath -w` and hands the resulting Windows/UNC path to Windows `Invoke-Item`, including browser-renderable documents, instead of assuming a Linux desktop association. The browser carrier applies the same loopback, same-origin restriction as `host.pickDirectory`.
 
-The `agentPreset.list` domain exposes the deployment's preset roster so a browser can offer a choice when starting a session; each row carries its `trust` (a `user` preset is exactly as privileged as the plugins it names) and whether it is the current default. A deployment composing no presets answers with an empty roster rather than an error, because sharing the host composition is a valid deployment. `agentPreset.select` recomposes one session's agent from a different preset, and is allowed only while the session is blank: once a turn has run, that history was produced under the preset's tools and swapping them would strand logged tool calls, so the attempt answers `agent-preset-locked`. The agent and the session survive — only the composition is swapped, and a failed swap restores the previous one.
+The `agentPreset.list` domain exposes the deployment's preset roster so a browser can offer a choice when starting a session; each row carries its `trust` (a `user` preset is exactly as privileged as the plugins it names), whether it is the current default, and — when the preset cannot compose a session — a `broken` reason, because a damaged directory still occupies its id and a surface must be able to show and delete it rather than offer it and fail the session start. A deployment composing no presets answers with an empty roster rather than an error, because sharing the host composition is a valid deployment. `agentPreset.select` recomposes one session's agent from a different preset, and is allowed only while the session is blank: once a turn has run, that history was produced under the preset's tools and swapping them would strand logged tool calls, so the attempt answers `agent-preset-locked`. The agent and the session survive — only the composition is swapped, and a failed swap restores the previous one.
 
 `agentPreset.read`, `copy`, `openDocument`, and `remove` manage the compositions themselves. `read` reports the text with its `trust`, for the read-only viewer. Authoring is copy-only: `copy` takes `{ from, agentPreset, name? }` — two ids the Host resolves against its own roots plus an optional display name — and copies the source's whole directory, so no composition text crosses the wire and a copy is exactly as loadable as its source; an uncontainable or already-taken id answers `agent-preset-invalid`, and `remove` refuses a shipped preset as `agent-preset-read-only`. `openDocument` hands one locally authored preset's DIRECTORY to the platform opener — the request carries an id, never a path, so no browser payload can select an arbitrary filesystem target; where the deployment has no native opener the reply is `{ opened: false, path }` for the surface to show as text, a shipped preset is refused like `remove`, and the gateway's `nativeOpen` config pins the capability where platform detection (`canOpenNativePath`) would mislead. These four are loopback-pinned in [`dsh-client-connection`](../../client/connection/README.md): a composition names the plugins a session runs, so reading one is reconnaissance, and copy/remove/openDocument manage the roster and drive the host desktop. `list` and `select` stay ordinary — the roster carries ids and trust and every preset picker needs it, and choosing a preset grants nothing `session.create`'s own `agentPreset` did not, over a default that already carries bash. `list` reports two path-free capability flags: `authorable`, whether the deployment configures a root a new preset could be copied to, and `hasDocument`, whether `openDocument` would open natively rather than answer a path.
 

packages/host/apiproxy/README.zh.md

@@ -46,7 +46,7 @@ Workspace 列表与 Session 列表是相互独立的重连基线。`workspace.cr
 
 `host.openPath` 会用操作系统的默认应用打开一个文件系统路径（macOS 为 `open`，Windows 为 `Invoke-Item`，桌面 Linux 为 `xdg-open`）。对于 `.html`、`.htm`、`.xhtml` 与 `.svg`，macOS 和桌面 Linux 会优先使用能够确定的默认浏览器；无法确定时回退到上述应用交接。WSL 会通过 `wslpath -w` 转换每个 Linux 路径，并将所得 Windows/UNC 路径交给 Windows `Invoke-Item`，浏览器可渲染的文档也不例外，而非假定存在 Linux 桌面文件关联。浏览器载体对其施加与 `host.pickDirectory` 相同的回环、同源限制。
 
-`agentPreset.list` 领域向浏览器暴露部署的 preset 名单，使其在开启会话时能够提供选择；每一行携带它的 `trust`（`user` preset 的权限恰好等于它所引用的插件）以及它是否为当前默认值。未组装任何 preset 的部署返回空名单而非错误，因为共用宿主组装本身就是一种有效部署。`agentPreset.select` 用另一个 preset 重组某个会话的 agent，且仅在会话空白时允许：一旦跑过任何轮次，那段历史就是在该 preset 的工具下产生的，替换会留下无法执行的已记录 tool call，此时返回 `agent-preset-locked`。agent 与会话都不销毁——只替换组装，且替换失败会恢复原来的组装。
+`agentPreset.list` 领域向浏览器暴露部署的 preset 名单，使其在开启会话时能够提供选择；每一行携带它的 `trust`（`user` preset 的权限恰好等于它所引用的插件）、它是否为当前默认值，以及——当该 preset 无法组装会话时——一条 `broken` 原因：损坏的目录仍占着它的 id，界面必须能展示并删除它，而不是把它端出来然后在会话启动时失败。未组装任何 preset 的部署返回空名单而非错误，因为共用宿主组装本身就是一种有效部署。`agentPreset.select` 用另一个 preset 重组某个会话的 agent，且仅在会话空白时允许：一旦跑过任何轮次，那段历史就是在该 preset 的工具下产生的，替换会留下无法执行的已记录 tool call，此时返回 `agent-preset-locked`。agent 与会话都不销毁——只替换组装，且替换失败会恢复原来的组装。
 
 `agentPreset.read`、`copy`、`openDocument` 与 `remove` 负责管理组装本身。`read` 返回文本连同它的 `trust`，供只读查看器使用。创作只有复制一种写入：`copy` 接收 `{ from, agentPreset, name? }`——两个由 Host 对照自身根目录解析的 id 加一个可选显示名——并整目录复制来源，因此组装文本不经过传输层，副本与其来源同等可加载；不可约束或已被占用的 id 回答 `agent-preset-invalid`，`remove` 对随附 preset 回答 `agent-preset-read-only`。`openDocument` 把一个本地创作 preset 的**目录**交给平台打开器——请求只携带 id、绝不携带路径，因此没有任何浏览器载荷能选中任意文件系统目标；部署没有原生打开器时回答 `{ opened: false, path }` 供界面以文本展示，随附 preset 与 `remove` 一样被拒绝，而网关的 `nativeOpen` 配置可在平台探测（`canOpenNativePath`）失真处钉死该能力。这四个方法在 [`dsh-client-connection`](../../client/connection/README.md) 中被固定在环回地址：组装指明了一个会话所运行的插件，因此读取它是侦察，而 copy/remove/openDocument 管理名单并驱动宿主桌面。`list` 与 `select` 保持为普通方法——名单只携带 id 与信任级别，每个 preset 选择器都需要它；而选择一个 preset 并不比 `session.create` 自带的 `agentPreset` 多给任何能力，何况默认 preset 本就带着 bash。`list` 报告两个不含路径的能力标志：`authorable`，即部署是否配置了可供复制新 preset 的根目录；`hasDocument`，即 `openDocument` 会原生打开、还是回答一个路径。
 

packages/host/apiproxy/src/api-proxy.ts

@@ -2678,6 +2678,7 @@ export function createApiProxy(ctx: Context, defaults: ApiProxyDefaults): ApiPro
             isDefault: preset.id === defaultId,
             ...preset.name === undefined ? {} : { name: preset.name },
             ...preset.description === undefined ? {} : { description: preset.description },
+            ...preset.broken === undefined ? {} : { broken: preset.broken },
           })),
           authorable: presets.authorable,
           hasDocument: canOpenPaths(),

packages/host/apiproxy/src/api/agent-presets.schema.ts

@@ -16,6 +16,7 @@ export const agentPresetEntrySchema = z.object({
   isDefault: z.boolean(),
   name: z.string().optional(),
   description: z.string().optional(),
+  broken: z.string().min(1).optional(),
 }) satisfies z.ZodType<Wire<AgentPresetEntry>>
 
 /** agentPreset.list request payload. */

packages/host/apiproxy/src/api/agent-presets.ts

@@ -33,6 +33,13 @@ export interface AgentPresetEntry {
   readonly name?: string
   /** One sentence on what the preset is for, when it published one. */
   readonly description?: string
+  /**
+   * Why this preset cannot compose a session, absent when it can. A broken
+   * preset stays listed — its directory still occupies the id, so a surface
+   * must be able to show and delete it — but offering it for selection would
+   * only defer this reason to a failed session start.
+   */
+  readonly broken?: string
 }
 
 /** agent-preset-domain unary methods (the map key agentPreset.* of RpcMethodMap). */