fix(gateway): notify_list/get/ack call NotificationDeliveryService (not Service)

Wave 1 wired notify_list/get/ack into ContentActions but pointed them at
`self.notifications` (which is NotificationService — sender side, with
send_blocker_notification / send_qa_ready_notification / etc.). The
read methods (list_for_agent, get_for_recipient_and_mark_read,
acknowledge) live on `NotificationDeliveryService` instead.

Smoke run 2026-05-11 surfaced this immediately:
  AttributeError: 'NotificationService' object has no attribute 'list_for_agent'

Fixes:
- roboco/api/deps.py — import NotificationDeliveryService and wire it
  in as a new ContentActionsDeps field `notification_delivery`.
- roboco/services/gateway/content_actions.py — add notification_delivery
  to ContentActionsDeps (Optional with `None` default for back-compat
  with any tests that don't supply it). Point notify_list, notify_get,
  notify_ack at self._deps.notification_delivery.
- tests/unit/gateway/test_content_actions.py — _make_deps adds a default
  AsyncMock for notification_delivery so existing tests continue to pass.

Quality: ruff + mypy clean. 505 unit tests pass.

roboco/api/deps.py

@@ -31,6 +31,7 @@ from roboco.services.git import GitService
 from roboco.services.journal import JournalService
 from roboco.services.messaging import MessagingService
 from roboco.services.notification import NotificationService
+from roboco.services.notification_delivery import NotificationDeliveryService
 from roboco.services.permissions import AgentContext, PermissionService
 from roboco.services.repositories import resolve_agent_identity, resolve_agent_uuid
 from roboco.services.task import TaskService
@@ -528,6 +529,7 @@ async def get_content_actions(
             journal=JournalService(db_session),
             workspace=WorkspaceService(db_session),
             notifications=NotificationService(),
+            notification_delivery=NotificationDeliveryService(db_session),
         )
     )
 

roboco/services/gateway/content_actions.py

@@ -200,6 +200,10 @@ class ContentActionsDeps:
     journal: Any
     workspace: Any
     notifications: Any
+    # Wave 1 added inbox-read verbs (notify_list/get/ack) that live on
+    # `NotificationDeliveryService`, not `NotificationService`. Keeping
+    # them separate so the sender vs receiver concerns stay split.
+    notification_delivery: Any = None
 
 
 _VALID_NOTIFY_PRIORITIES: frozenset[str] = frozenset(p.value for p in _comms.Priority)
@@ -788,7 +792,7 @@ class ContentActions:
         the verb is documented to soft-block on unread notifications, but
         previously there was no way for the agent to read or acknowledge them.
         """
-        items = await self.notifications.list_for_agent(
+        items = await self._deps.notification_delivery.list_for_agent(
             agent_id=agent_id,
             unread_only=unread_only,
             pending_ack_only=pending_ack_only,
@@ -824,7 +828,7 @@ class ContentActions:
     ) -> Envelope:
         """Read one notification (also marks it read)."""
         try:
-            n = await self.notifications.get_for_recipient_and_mark_read(
+            n = await self._deps.notification_delivery.get_for_recipient_and_mark_read(
                 notification_id=notification_id,
                 agent_id=agent_id,
             )
@@ -892,7 +896,7 @@ class ContentActions:
         Returns ``not_authorized`` if the caller isn't a recipient.
         """
         try:
-            n = await self.notifications.acknowledge(
+            n = await self._deps.notification_delivery.acknowledge(
                 notification_id=notification_id,
                 agent_id=agent_id,
                 ack_type="received",

tests/unit/gateway/test_content_actions.py

@@ -35,6 +35,7 @@ def _make_deps(**overrides: AsyncMock) -> ContentActionsDeps:
     journal = overrides.get("journal", AsyncMock())
     workspace = overrides.get("workspace", AsyncMock())
     notifications = overrides.get("notifications", AsyncMock())
+    notification_delivery = overrides.get("notification_delivery", AsyncMock())
     return ContentActionsDeps(
         task=task,
         git=git,
@@ -43,6 +44,7 @@ def _make_deps(**overrides: AsyncMock) -> ContentActionsDeps:
         journal=journal,
         workspace=workspace,
         notifications=notifications,
+        notification_delivery=notification_delivery,
     )