feat(gateway): propagate sessions to subtasks + auto-emit milestone progress

Task #156 (sessions): pre-gateway flow created a session for the whole
task tree at once, so subtasks were visible in the PM's group chat the
moment they existed. The gateway creates subtasks one-by-one via
delegate(), losing that wiring. Added
MessagingService.propagate_sessions_to_subtask and threaded it through
the choreographer's _create_subtask_from_inputs. ChoreographerDeps grew
an optional `messaging` field so existing test wirings keep working.

Task #155 (progress): smoke-9 had zero progress entries because the dev
never called progress() explicitly. Added _record_milestone_progress and
fire it server-side from two natural milestones — open_pr ("opened PR
#N", 70%) and i_am_done ("submitted for QA review", 90%). Best-effort
write (contextlib.suppress) so a progress failure cannot break the verb
path. Extracted _open_pr_success_envelope to keep cyclomatic rank ≤ B.

tests/unit/gateway/test_delegate_propagates_sessions.py

@@ -0,0 +1,138 @@
+"""Task #156: delegate() must thread parent sessions onto the new subtask.
+
+Pre-gateway flow created sessions for whole task trees at once, so subtasks
+were visible in the group chat the PM was already using. The gateway's
+delegate() creates subtasks one-by-one — without this step the new agent
+spawns into an empty channel and can't see the PM's prior discussion.
+"""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from typing import Any
+from unittest.mock import AsyncMock, MagicMock
+from uuid import uuid4
+
+import pytest
+from roboco.services.gateway.choreographer import Choreographer, ChoreographerDeps
+from roboco.services.gateway.choreographer._impl import DelegateInputs
+
+
+def _make_deps(**overrides: Any) -> ChoreographerDeps:
+    base: dict[str, Any] = {
+        "task": AsyncMock(),
+        "work_session": AsyncMock(),
+        "git": AsyncMock(),
+        "a2a": AsyncMock(),
+        "journal": AsyncMock(),
+        "audit": AsyncMock(),
+        "evidence_repo": AsyncMock(),
+        "messaging": AsyncMock(),
+    }
+    base.update(overrides)
+    task = base["task"]
+    task.session = MagicMock()
+    task.session.begin_nested = MagicMock(
+        return_value=MagicMock(
+            __aenter__=AsyncMock(return_value=None),
+            __aexit__=AsyncMock(return_value=False),
+        )
+    )
+    repo = base["evidence_repo"]
+    for method in (
+        "list_unread_a2a",
+        "list_unread_mentions",
+        "list_pending_notifications",
+        "task_metadata_gaps",
+        "recent_team_activity",
+        "blockers_in_lane",
+        "journal_highlights_for_task",
+    ):
+        getattr(repo, method).return_value = []
+    _ldef = base["journal"].latest_decision_at.return_value
+    if type(_ldef).__name__ in ("MagicMock", "AsyncMock"):
+        base["journal"].latest_decision_at.return_value = datetime.now(UTC)
+    return ChoreographerDeps(**base)
+
+
+@pytest.mark.asyncio
+async def test_create_subtask_propagates_parent_sessions() -> None:
+    """When the choreographer creates a subtask, the parent's session
+    links are auto-attached to it via MessagingService.propagate_sessions_to_subtask.
+    """
+    pm_id = uuid4()
+    parent_id = uuid4()
+    new_task_id = uuid4()
+    parent = MagicMock(
+        id=parent_id,
+        project_id=uuid4(),
+        team="backend",
+        status="in_progress",
+        task_type="planning",
+        sequence=0,
+        assigned_to=pm_id,
+    )
+    new_task = MagicMock(id=new_task_id, status="pending")
+    task_svc = AsyncMock()
+    task_svc.create_subtask.return_value = new_task
+    messaging = AsyncMock()
+    messaging.propagate_sessions_to_subtask.return_value = []
+    deps = _make_deps(task=task_svc, messaging=messaging)
+    c = Choreographer(deps)
+
+    inputs = DelegateInputs(
+        title="Backend slice",
+        description="API + DB",
+        acceptance_criteria=["api works", "schema migrated"],
+        assigned_to="be-dev-1",
+        team="backend",
+        task_type="code",
+        nature="technical",
+        estimated_complexity="medium",
+    )
+    result = await c._create_subtask_from_inputs(pm_id, parent_id, parent, inputs)
+    assert result is new_task
+
+    messaging.propagate_sessions_to_subtask.assert_awaited_once_with(
+        parent_task_id=parent_id,
+        subtask_id=new_task_id,
+        added_by=pm_id,
+    )
+
+
+@pytest.mark.asyncio
+async def test_create_subtask_no_messaging_skips_propagation() -> None:
+    """When messaging dep is None (e.g. lightweight test wiring), the
+    subtask is still created — propagation is a soft enhancement, not a
+    hard requirement."""
+    pm_id = uuid4()
+    parent_id = uuid4()
+    new_task_id = uuid4()
+    parent = MagicMock(
+        id=parent_id,
+        project_id=uuid4(),
+        team="backend",
+        status="in_progress",
+        task_type="planning",
+        sequence=0,
+        assigned_to=pm_id,
+    )
+    new_task = MagicMock(id=new_task_id, status="pending")
+    task_svc = AsyncMock()
+    task_svc.create_subtask.return_value = new_task
+    deps = _make_deps(task=task_svc, messaging=None)
+    c = Choreographer(deps)
+
+    inputs = DelegateInputs(
+        title="Backend slice",
+        description="API + DB",
+        acceptance_criteria=["api works"],
+        assigned_to="be-dev-1",
+        team="backend",
+        task_type="code",
+        nature="technical",
+        estimated_complexity="medium",
+    )
+    # Must not raise even though messaging is None.
+    result = await c._create_subtask_from_inputs(pm_id, parent_id, parent, inputs)
+    assert result is new_task

tests/unit/gateway/test_milestone_progress.py

@@ -0,0 +1,68 @@
+"""Task #155: server-side auto-progress on lifecycle milestones.
+
+Smoke-9 ended with zero progress entries because the dev never called
+progress() explicitly. The fix: server emits progress entries at
+deterministic lifecycle milestones (open_pr → "opened PR #N",
+i_am_done → "submitted for QA review") so the panel + audit have entries
+regardless of agent chattiness. Progress is observability — write failures
+must not break the verb path.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import AsyncMock
+from uuid import uuid4
+
+import pytest
+from roboco.services.gateway.choreographer import Choreographer, ChoreographerDeps
+
+
+@pytest.mark.asyncio
+async def test_record_milestone_progress_calls_add_progress() -> None:
+    """The helper proxies to TaskService.add_progress with the right args."""
+    task_svc = AsyncMock()
+    deps = ChoreographerDeps(
+        task=task_svc,
+        work_session=AsyncMock(),
+        git=AsyncMock(),
+        a2a=AsyncMock(),
+        journal=AsyncMock(),
+        audit=AsyncMock(),
+        evidence_repo=AsyncMock(),
+        messaging=AsyncMock(),
+    )
+    c = Choreographer(deps)
+
+    task_id = uuid4()
+    agent_id = uuid4()
+    await c._record_milestone_progress(task_id, agent_id, "opened PR #20", 70)
+
+    task_svc.add_progress.assert_awaited_once_with(
+        task_id=task_id,
+        agent_id=agent_id,
+        message="opened PR #20",
+        percentage=70,
+    )
+
+
+@pytest.mark.asyncio
+async def test_record_milestone_progress_swallows_errors() -> None:
+    """Progress is observability. A failing add_progress must not raise
+    so the verb body's main flow is unaffected."""
+    task_svc = AsyncMock()
+    task_svc.add_progress.side_effect = RuntimeError("db lock contention")
+    deps = ChoreographerDeps(
+        task=task_svc,
+        work_session=AsyncMock(),
+        git=AsyncMock(),
+        a2a=AsyncMock(),
+        journal=AsyncMock(),
+        audit=AsyncMock(),
+        evidence_repo=AsyncMock(),
+        messaging=AsyncMock(),
+    )
+    c = Choreographer(deps)
+
+    # Must NOT raise.
+    await c._record_milestone_progress(uuid4(), uuid4(), "submitted for QA review", 90)
+    task_svc.add_progress.assert_awaited_once()

tests/unit/services/test_propagate_sessions_to_subtask.py

@@ -0,0 +1,98 @@
+"""Task #156: MessagingService.propagate_sessions_to_subtask.
+
+Tests the helper's call shape and idempotency contract without going
+through the DB. Integration coverage (real DB, real linking) lives in
+``tests/integration/test_messaging_service.py``.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+from unittest.mock import AsyncMock, MagicMock
+from uuid import uuid4
+
+import pytest
+from roboco.models.session import SessionTaskRelationshipType
+from roboco.services.messaging import MessagingService
+
+
+def _link(session_id: object, relationship_type: str) -> MagicMock:
+    link = MagicMock()
+    link.session_id = session_id
+    link.relationship_type = relationship_type
+    return link
+
+
+@pytest.mark.asyncio
+async def test_propagate_links_every_parent_session_to_subtask() -> None:
+    """Every link on the parent gets re-attached to the new subtask."""
+    svc = MessagingService.__new__(MessagingService)
+    parent_session = uuid4()
+    review_session = uuid4()
+    svc.get_sessions_for_task = AsyncMock(  # type: ignore[method-assign]
+        return_value=[
+            _link(parent_session, "discussion"),
+            _link(review_session, "review"),
+        ]
+    )
+
+    calls: list[dict[str, Any]] = []
+
+    async def fake_link(**kwargs: Any) -> Any:
+        calls.append(kwargs)
+        link = MagicMock()
+        link.session_id = kwargs["session_id"]
+        link.task_id = kwargs["task_id"]
+        return link
+
+    svc.link_session_to_task = fake_link  # type: ignore[method-assign]
+
+    parent_id = uuid4()
+    subtask_id = uuid4()
+    added_by = uuid4()
+    expected_sessions = {parent_session, review_session}
+    out = await svc.propagate_sessions_to_subtask(parent_id, subtask_id, added_by)
+    assert len(out) == len(expected_sessions)
+    assert {c["session_id"] for c in calls} == expected_sessions
+    # Every propagated link must be non-primary — primary is the subtask's
+    # own slot, never inherited from the parent.
+    assert all(c["is_primary"] is False for c in calls)
+    # Every call must target the new subtask (not the parent).
+    assert {c["task_id"] for c in calls} == {subtask_id}
+    # Relationship types preserved.
+    rels = {c["relationship_type"] for c in calls}
+    assert SessionTaskRelationshipType.DISCUSSION in rels
+    assert SessionTaskRelationshipType.REVIEW in rels
+
+
+@pytest.mark.asyncio
+async def test_propagate_no_parent_sessions_returns_empty() -> None:
+    """When the parent has no session links, propagation is a no-op."""
+    svc = MessagingService.__new__(MessagingService)
+    svc.get_sessions_for_task = AsyncMock(return_value=[])  # type: ignore[method-assign]
+    svc.link_session_to_task = AsyncMock()  # type: ignore[method-assign]
+
+    out = await svc.propagate_sessions_to_subtask(uuid4(), uuid4(), uuid4())
+    assert out == []
+    svc.link_session_to_task.assert_not_awaited()
+
+
+@pytest.mark.asyncio
+async def test_propagate_unknown_relationship_type_defaults_to_discussion() -> None:
+    """Garbage relationship_type on the parent link doesn't crash; it
+    defaults to DISCUSSION so the subtask is still linked."""
+    svc = MessagingService.__new__(MessagingService)
+    svc.get_sessions_for_task = AsyncMock(  # type: ignore[method-assign]
+        return_value=[_link(uuid4(), "definitely-not-a-real-type")]
+    )
+    calls: list[dict[str, Any]] = []
+
+    async def fake_link(**kwargs: Any) -> Any:
+        calls.append(kwargs)
+        return MagicMock()
+
+    svc.link_session_to_task = fake_link  # type: ignore[method-assign]
+
+    await svc.propagate_sessions_to_subtask(uuid4(), uuid4(), uuid4())
+    assert len(calls) == 1
+    assert calls[0]["relationship_type"] == SessionTaskRelationshipType.DISCUSSION