feat(tool-fs): editor-facing presentation for read/write/edit

The fs tools rendered as generic cards (title = tool name, raw file content) in
an ACP editor. Give them tool-owned presentation like bash/subagent have:

- read → title "Read <path>", kind read, offset/limit as rawInput
- write → title "Write <path>", kind edit
- edit → title "Edit <path>", kind edit, a clipped old→new rawInput summary

Add a provider-neutral `locations: { path, line? }[]` to ToolCallPresentation —
the files a call reads/modifies — so a capable editor can follow along / jump to
the file (read carries its offset as the line). The ACP bridge forwards it onto
the wire `tool_call` (ResolvedCallPresentation + call() + the tool_call build in
streamSessionEventUpdate). This flips the `locations` cell in the ACP feature
matrix to supported. The SDK already carries `tool_call.locations`
(ToolCallLocation `{ path, line? }`), so no ACP types leak into dsh-tools.

presentResult is intentionally omitted: it only receives `{ content, isError }`,
not the write/edit outcome, so titling by create-vs-overwrite or replacement
count would mean parsing the model-facing text — the static title stays.

Tests: pure presentCall assertions for all three tools incl. locations and the
edit rawInput clip; a bridge test drives the REAL fs tools through ToolPresenter
and asserts locations reaches the wire tool_call (proven to fail without the
forwarding line). New withFs harness option + dsh-fs devDeps on dsh-acp.

packages/core/tools/src/index.ts

@@ -109,6 +109,16 @@ export interface ToolCallPresentation {
    * {@link terminal} block (if any) as a terminal card.
    */
   content?: ContentBlock[]
+  /**
+   * Files this call reads or modifies, so a capable UI can "follow along" —
+   * highlight or jump to the file (and line) as the tool runs. Provider-neutral
+   * `{ path, line? }` pairs; a UI bridge maps them to its own affordance (the ACP
+   * bridge forwards them as `tool_call.locations`). `path` is what the tool
+   * operated on (the model-facing path); `line` is an optional 1-based line to
+   * focus (e.g. a read's offset). Omit for a call that touches no file (e.g.
+   * `bash`).
+   */
+  locations?: { path: string; line?: number }[]
   /**
    * Ask a capable UI to render this call as a TERMINAL (a command running in a
    * working directory), not a generic tool card — set by a tool whose call IS a