MegaTask umbrella e2e scenario + batch root-subtask completion fix; comms dead-code deletion (#296)

* chore(panel): delete the five dead comms components

The comms audit found communications-view, channel-sidebar,
channel-item, message-list, and message-item exported but rendered by
no page — the live /communications page and the session detail render
their own inline content and import only MessageComposer and
MessageTypeBadge, which stay. Verified zero consumers outside the dead
cluster before deletion; panel gates green (tsc, lint, 187 tests).

* feat(tests): e2e scenario 4 — MegaTask umbrella; fix batch root-subtask completion wall

Scenario 4 seeds an umbrella + two dependency-linked root-subtasks:
sequencing hold proven (unmet_dependency on RS2's i_will_plan while RS1
lives), RS1 completed through the entire real chain to a master merge,
hold lifts, RS2 completes, umbrella closes branchless via ceo-approve
and never carries a PR.

Product fix it surfaced on first run: _main_pm_complete_guard and
escalate_to_ceo refused ANY parented task as 'not a root', but a batch
root-subtask is parented (the umbrella) BY DESIGN — both sites now
consult is_batch_root_subtask, plain subtasks stay refused. Live
root-subtasks previously needed CEO god-mode to close. Regression
tests added; built subagent-driven (Sonnet 5) and reviewed.

---------

Co-authored-by: Renn F <rennf93@users.noreply.github.com>

tests/integration/test_task_service_transitions.py

@@ -1367,6 +1367,27 @@ async def test_escalate_to_ceo_returns_none_for_subtask(
     assert out is None
 
 
+@pytest.mark.asyncio
+async def test_escalate_to_ceo_allows_batch_root_subtask(
+    task_setup: dict, db_session: AsyncSession
+) -> None:
+    """A MegaTask root-subtask IS parented (the umbrella) yet carries its own
+    project/branch/PR and behaves as a root for git/CEO purposes — unlike a
+    plain subtask, it must NOT be refused by the parent-task-only check."""
+    svc = task_setup["svc"]
+    umbrella = await svc.create(_req(task_setup))
+    sub = await svc.create(_req(task_setup, parent_task_id=umbrella.id))
+    sub.status = TaskStatus.AWAITING_PM_REVIEW
+    sub.batch_id = uuid4()
+    sub.pr_number = 7
+    await db_session.flush()
+    escalated = await svc.escalate_to_ceo(
+        sub.id, agent_role="main_pm", notes="root-subtask ready for CEO sign-off"
+    )
+    assert escalated is not None
+    assert escalated.status == TaskStatus.AWAITING_CEO_APPROVAL
+
+
 @pytest.mark.asyncio
 async def test_escalate_to_ceo_returns_none_when_no_pr(
     task_setup: dict, db_session: AsyncSession