fix(mcp): list tools return rows that say what a record is, not what it says (#4061)

list_tasks returned every row's to_dict(), body included: a project's todo list
came to 93-165k characters, past what an MCP client accepts inline, so the list
arrived as a file to page through (the #4045 failure, one call over).

- notes.brief_row: id, title, type, project, tags, updated_at; for tasks,
  status, kind, priority, milestone id and title; description, parent and due
  date only when set.
- milestones.titles_for: one query for the milestone titles a page of rows
  names.
- Brief rows on list_tasks, list_notes, get_milestone's steps, get_system and
  list_system_records. get_task / get_note / get_snippet read a record in full,
  and each docstring says so.
- tests/test_list_rows_brief.py pins the ceiling: 100 rows of ~5k-character
  step plans stay under 40k characters.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy

src/scribe/mcp/tools/tasks.py

@@ -22,6 +22,7 @@ from scribe.mcp._context import current_user_id
 from scribe.mcp.tools import systems as systems_tools
 from scribe.services import access as access_svc
 from scribe.services import dedup as dedup_svc
+from scribe.services import milestones as milestones_svc
 from scribe.services import notes as notes_svc
 # Imported by NAME, not reached through notes_svc: minted_kind is pure
 # validation, not a service call, and a test that stubs the service module to
@@ -58,7 +59,10 @@ async def list_tasks(
         kind: Filter by task kind — 'work', 'issue', 'spike' (or the retired
             'plan'). Omit (empty) for all kinds.
 
-    Results are ordered by last-updated descending.
+    Results are ordered by last-updated descending. Each row says what the task
+    is and where it sits — id, title, status, kind, priority, milestone (id and
+    title), tags, updated_at, plus description, parent and due date when set —
+    and not what it says: read one in full with get_task(id).
     """
     uid = current_user_id()
     rows, total = await notes_svc.list_notes(
@@ -70,7 +74,8 @@ async def list_tasks(
         limit=max(1, min(limit, 100)),
         offset=max(0, offset),
     )
-    return {"tasks": [n.to_dict() for n in rows], "total": total}
+    titles = await milestones_svc.titles_for({n.milestone_id for n in rows})
+    return {"tasks": [notes_svc.brief_row(n, titles) for n in rows], "total": total}
 
 
 async def get_task(task_id: int) -> dict: