feat(notes): accept and return description field through service and routes

create_note service accepts a new description kwarg and forwards it to the
Note constructor. PUT/PATCH/POST routes include description in the field
whitelist. update_note already passed **fields through setattr, so the new
column is reachable without touching that signature.

tests/test_notes_description_field.py

@@ -0,0 +1,74 @@
+"""Tests for the description-field roundtrip through the notes service.
+
+The description field is the user-stated goal/context on a task; distinct
+from `body` which (post-Task-as-Durable-Record) becomes the LLM-maintained
+consolidation summary.
+"""
+from unittest.mock import AsyncMock, MagicMock, patch
+
+
+def _mock_session_for_update(mock_note):
+    mock_session = AsyncMock()
+    mock_result = MagicMock()
+    mock_result.scalars.return_value.first.return_value = mock_note
+    mock_session.execute = AsyncMock(return_value=mock_result)
+    mock_session.commit = AsyncMock()
+    mock_session.refresh = AsyncMock()
+    mock_session.__aenter__ = AsyncMock(return_value=mock_session)
+    mock_session.__aexit__ = AsyncMock(return_value=False)
+    return mock_session
+
+
+async def test_update_note_persists_description():
+    """update_note(description=...) should assign to note.description.
+
+    update_note already accepts **fields and uses setattr, so this exercises
+    that the new model column is reachable through the existing dynamic-fields
+    path (no service-layer change required beyond the model column).
+    """
+    mock_note = MagicMock()
+    # Pre-existing state — None description, no recurrence, status untouched.
+    mock_note.description = None
+    mock_note.status = None
+    mock_note.recurrence_rule = None
+    mock_note.project_id = None
+
+    with patch(
+        "fabledassistant.services.notes.async_session",
+        return_value=_mock_session_for_update(mock_note),
+    ):
+        from fabledassistant.services.notes import update_note
+        await update_note(1, 1, description="the goal text")
+
+    assert mock_note.description == "the goal text"
+
+
+async def test_create_note_forwards_description_to_model():
+    """create_note(description=...) should pass description into the Note
+    constructor so it gets persisted alongside title/body/etc."""
+    captured: dict = {}
+
+    class FakeNote:
+        def __init__(self, **kw):
+            captured.update(kw)
+            self.id = 1
+            self.project_id = kw.get("project_id")
+            for k, v in kw.items():
+                setattr(self, k, v)
+
+    mock_session = AsyncMock()
+    mock_session.add = MagicMock()
+    mock_session.commit = AsyncMock()
+    mock_session.refresh = AsyncMock()
+    mock_session.__aenter__ = AsyncMock(return_value=mock_session)
+    mock_session.__aexit__ = AsyncMock(return_value=False)
+
+    with patch(
+        "fabledassistant.services.notes.async_session", return_value=mock_session
+    ), patch("fabledassistant.services.notes.Note", FakeNote):
+        from fabledassistant.services.notes import create_note
+        await create_note(
+            user_id=1, title="renew cert", description="the goal text",
+        )
+
+    assert captured.get("description") == "the goal text"