feat(acp): tool-owned tool-call UI presentation (title/command/output)

In Zed the tool-call card showed only "bash" — the bare tool name — instead
of what the command does. Fix it by letting each TOOL own how its calls render,
rather than the bridge special-casing names.

dsh-tools: add an optional two-state presentation seam to ToolDefinition /
defineTool — `presentCall(args)` (pending: title, kind, rawInput) and
`presentResult(args, result)` (completed: title?, content?). Provider-neutral
`ToolCallKind`/`ToolCallPresentation`/`ToolResultPresentation` vocabulary so
tools never depend on ACP. defineTool soft-validates args (display runs on log
replay, so a malformed/old shape returns undefined instead of throwing).

dsh-tool-bash: bash declares presentCall (model `description` → title, exact
`command` → rawInput, kind execute) and presentResult (wrap output in a fenced
```console block — a UI-only affordance kept out of the model-facing result);
bash_output/bash_kill present task-scoped titles.

dsh-acp: inject `tools`; a per-session `ToolPresenter` looks the tool up by name
and maps its neutral presentation to the ACP tool_call/tool_call_update wire
shape, with a generic fallback (title = name) for tools that declare nothing.
Because the `tool/result` event carries only {callId, content, isError}, the
presenter keeps a small bridge-local map of ONLY in-flight calls' (name, args),
keyed by callId and removed as each result is presented — no event-schema or
core change. Replay uses a throwaway presenter so loaded sessions render
identically to live ones.

Tests: dsh-tools defineTool presenters (typed args, soft-validate), tool-bash
bash/bash_output/bash_kill presenters, acp ToolPresenter (tool-owned mapping,
unknown-callId fallback, in-flight-only map), and an end-to-end turn through the
bridge. The key-gated e2e now asserts a real bash call's title is the model
description (not "bash") and rawInput is the command — verified against the real
DeepSeek model. The test harness derives its inject from the bridge's exported
`inject` so it can't drift again.

packages/tool-bash/README.md

@@ -32,6 +32,10 @@ Result text: stdout, then a `[stderr]` section, then status markers — `[timed
 
 The owning agent is recorded per task id at spawn and kept for the lifetime of the loaded plugin instance (it is **not** cleared on completion). `bash_output`/`bash_kill` reject a task owned by a *different* agent with `task <id> belongs to another session` (a task started with no agent — a non-loop caller — has no owner and is open to anyone; a call with no `exec.agent` cannot access an owned task). Task ids are global and predictable, so under multi-session ACP this ownership check is the fence that stops one session's agent from reading or killing another session's background task. (`TODO(tool-bash-owner-hmr)`: an independent HMR reload of this plugin starts a fresh map, so a task spawned before the reload becomes un-owned — acceptable as HMR is dev-only and the session boundary is one user's cooperative editor; a durable fix attaches ownership to the executor/task lifetime.)
 
+## UI presentation
+
+These tools own how their calls render in a UI (an editor's tool-call card) via the `dsh-tools` `presentCall`/`presentResult` seam — a UI never special-cases tool names. For `bash`: the model-written `description` is the always-visible **title** (e.g. "List files in the current directory"), the exact `command` is the **rawInput** (the verbatim command stays visible in a detail view without crowding the title), `kind` is `execute` (terminal/run treatment), and the completed output is wrapped in a fenced ` ```console ` block — a UI-only affordance, so the model-facing result text stays unfenced. `bash_output`/`bash_kill` present a task-scoped title ("Read output from background task bash-3" / "Kill background task bash-3") with the task id as rawInput. These methods are pure/display-only (they also run on `session/load` replay), and a malformed/older logged arg shape falls back to a generic presentation rather than throwing. See `packages/tools` ("Tool-owned UI presentation") and `packages/acp` ("Tool-call presentation").
+
 ## Background completion notices
 
 When a background task finishes, a short notice is injected into the owning agent's session (`agent.inject()`, source `{kind: 'plugin', plugin: 'tool-bash'}`). Injection is **durable context for the next model request, not a wake-up** — an idle agent stays idle until something sends a message. That's why the tool descriptions tell the model to poll with `bash_output`.