fix(orchestration): complete tasks on worker_done + coordinator UX fixes (#8030)

* fix(orchestration): complete worker tasks and improve coordinator UX

* Fix orchestration lifecycle sender resolution and peek/check compat hand

- Lifecycle sends (worker_done/heartbeat) now use ORCA_TERMINAL_HANDLE
  verbatim, skipping the liveness probe and pane remint that could
  block delivery during restarts or mismatch stale-runtime assignee
  handles.
- --peek now round-trips as {peek:true, unread:false} so older runtimes
  that strip unknown params degrade to non-destructive "all" instead of
  mark-read, with client-side filtering to restore peek semantics and a
  clear error when --peek --wait can't be honored.
- Reject combined read-mode flags (--unread/--peek/--all) before calling
  the runtime.
- Distinguish suppressed (already-consumed) lifecycle messages from
  ignored ones so send doesn't wake --wait waiters for stale heartbeats.
- Fix task summary truncation to avoid splitting UTF-16 surrogate pairs
  and to not misreport whitespace normalization as truncation.

* Add shared helper to abbreviate orchestration task specs for brief listi

- Normalizes whitespace and caps spec length at 160 chars, flagging
  truncation separately from whitespace-only changes
- Truncates on UTF-16 code point boundaries to avoid splitting
  surrogate pairs and emitting malformed strings

* Add pane-key identity to worker_done/heartbeat reconciliation and server

- Records the sender's pane key on messages and dispatch contexts so
  worker_done/heartbeat ownership can be verified by the remint-stable
  pane leaf instead of the terminal handle, which is reissued across
  restarts.
- Rejects lifecycle messages from a genuinely foreign pane while still
  tolerating handle remints, tab break-outs, and older CLIs that lack
  pane identity.
- Moves task-spec abbreviation server-side (orchestration.taskList
  --brief) so full specs no longer cross SSH/relay transports, with a
  client-side fallback for older runtimes; consolidates the shared
  abbreviation helper under src/shared.
- Adds a stderr warning when a pre-peek runtime's --peek response hits
  the 100-row cap, since older unread messages may be missing.

* Isolate ORCA_PANE_KEY in CLI test beforeEach to fix leaked senderPaneKey

Co-authored-by: Orca <help@stably.ai>

* Fix pane-key remint bypassing dispatch mutual-exclusion lock

- Dispatch locking only matched on assignee_handle, so a reminted
  terminal handle (tab break-out) could open a second concurrent
  dispatch on the same pane.
- Add leaf-UUID-based pane key comparison (parsePaneKey) as a
  secondary lock, falling back to exact handle match for legacy
  rows without pane keys.

* Update orchestration skill docs for lifecycle authority and CLI flag add

- Clarify that dispatch lifecycle is tied to taskId+dispatchId verified against
  the dispatched pane, not the terminal handle, since handles can be reminted
  after restart
- Document new `check --peek`/`--all` and `task-list --brief` flags, with
  fallback guidance for older CLIs that reject them
- Note that a valid worker_done auto-completes the task/dispatch, so workers
  shouldn't also call task-update manually

---------

Co-authored-by: Orca <help@stably.ai>

src/main/runtime/rpc/methods/worktree.test.ts

@@ -472,14 +472,18 @@ describe('worktree RPC methods', () => {
     const runtime = {
       getRuntimeId: () => 'test-runtime',
       showRepo: vi.fn().mockResolvedValue(repo),
-      createManagedWorktree: vi.fn().mockResolvedValue({ worktree: { id: 'wt-1' } })
+      createManagedWorktree: vi.fn().mockResolvedValue({
+        worktree: { id: 'wt-1' },
+        startupTerminal: { spawned: true, handle: 'term_agent' }
+      })
     } as unknown as OrcaRuntimeService
     const dispatcher = new RpcDispatcher({ runtime, methods: WORKTREE_METHODS })
 
-    await dispatcher.dispatch(
+    const response = await dispatcher.dispatch(
       makeRequest('worktree.create', {
         repo: 'repo-1',
         name: 'agent-startup',
+        startupAgent: 'codex',
         startupCommand: "codex 'summarize repo'",
         startupCommandDelivery: 'shell-ready',
         startupEnv: { ORCA_AGENT_MODE: 'direct' },
@@ -492,11 +496,17 @@ describe('worktree RPC methods', () => {
       })
     )
 
+    expect(response).toMatchObject({
+      ok: true,
+      result: { agentTerminalHandle: 'term_agent' }
+    })
+
     expect(runtime.createManagedWorktree).toHaveBeenCalledWith(
       expect.objectContaining({
         repoSelector: 'repo-1',
         name: 'agent-startup',
         activate: true,
+        startupAgent: 'codex',
         startup: {
           command: "codex 'summarize repo'",
           startupCommandDelivery: 'shell-ready',