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/ui/acp/src/index.ts

@@ -836,6 +836,7 @@ export function streamSessionEventUpdate(
           kind: present.kind,
           status: 'in_progress',
           ...present.rawInput !== undefined ? { rawInput: present.rawInput } : {},
+          ...present.locations !== undefined ? { locations: present.locations } : {},
           ...callContent.length > 0 ? { content: callContent } : {},
           ...asTerminal
             ? { _meta: { terminal_info: { terminal_id: event.data.callId, cwd: terminalCwd(present.terminal, terminal.cwd) } } }
@@ -926,6 +927,8 @@ interface ResolvedCallPresentation {
   rawInput?: unknown
   /** UI content shown on the pending call (e.g. a bash description text block above the card). */
   content?: ContentBlock[]
+  /** Files this call reads/modifies (mapped to ACP `tool_call.locations`), for editor follow-along. */
+  locations?: { path: string; line?: number }[]
   /** Tool's request to render as a terminal (the pending side carries the cwd). */
   terminal?: ToolTerminal
 }
@@ -1005,6 +1008,7 @@ export class ToolPresenter {
       kind: present.kind ?? 'other',
       rawInput: present.rawInput,
       ...present.content !== undefined ? { content: present.content } : {},
+      ...present.locations !== undefined ? { locations: present.locations } : {},
       ...present.terminal !== undefined ? { terminal: present.terminal } : {},
     }
   }