test(briefing): drop tests for removed legacy helpers

format_task, compute_task_hash, and split_changed_tasks were deleted
in 9eba6ac when the legacy one-shot briefing path was ripped out.
Their tests went with them.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_briefing_pipeline.py

@@ -12,52 +12,6 @@ async def test_get_or_create_profile_note_returns_body():
         assert body == ""
 
 
-def test_format_task_for_briefing():
-    """format_task() should return a compact single-line string."""
-    from fabledassistant.services.briefing_pipeline import format_task
-    task = {"title": "Write design doc", "status": "in_progress", "due_date": "2026-03-12", "priority": "high"}
-    result = format_task(task)
-    assert "Write design doc" in result
-    assert "in_progress" in result or "In Progress" in result
-
-
-
-def test_compute_task_snapshot_hash():
-    """compute_task_hash should return a stable SHA-256 hex string."""
-    from fabledassistant.services.briefing_pipeline import compute_task_hash
-
-    task = {"status": "todo", "priority": "high", "due_date": "2026-03-25", "title": "Write spec"}
-    h = compute_task_hash(task)
-    assert len(h) == 64  # SHA-256 hex
-    assert h == compute_task_hash(task)
-    assert h != compute_task_hash({**task, "status": "done"})
-
-
-@pytest.mark.asyncio
-async def test_split_changed_tasks_all_new():
-    """split_changed_tasks should return all tasks as changed when no snapshot exists."""
-    from fabledassistant.services.briefing_pipeline import split_changed_tasks
-
-    tasks = [
-        {"task_id": 1, "title": "A", "status": "todo", "priority": "none", "due_date": None},
-    ]
-
-    with patch(
-        "fabledassistant.services.briefing_pipeline.async_session"
-    ) as mock_cls:
-        mock_session = AsyncMock()
-        mock_session.__aenter__ = AsyncMock(return_value=mock_session)
-        mock_session.__aexit__ = AsyncMock(return_value=False)
-        mock_session.execute = AsyncMock(return_value=MagicMock(
-            scalars=MagicMock(return_value=MagicMock(all=MagicMock(return_value=[])))
-        ))
-        mock_cls.return_value = mock_session
-
-        changed, unchanged_count = await split_changed_tasks(user_id=1, tasks=tasks)
-        assert len(changed) == 1
-        assert unchanged_count == 0
-
-
 @pytest.mark.asyncio
 async def test_post_message_accepts_metadata():
     """post_message should accept an optional metadata dict and store it."""