refactor(scribe): retire calendar/events + person/place/list entities (backend)

Narrow Scribe to a Claude-Code work system-of-record (milestone #194,
decision note #1759). Wholesale removal per rule #22 — backend + schema half.

Calendar/events + CalDAV: delete models/event, services/{events,caldav,
caldav_sync}, routes/events, mcp/tools/events; strip event branches from
backup (bump v3->v4), dashboard (upcoming_events), trash, recent, and the
mcp server read-only allowlist + instructions.

Typed entities (person/place/list): delete mcp/tools/entities; drop the
notes.metadata (entity_meta) column from model/service/routes and the
knowledge browse service. note_type STAYS — it also marks 'process' notes.

Scheduler: event_scheduler -> recurrence_scheduler, keeping only the
recurring-task spawn job (drops event reminders + CalDAV sync).

Schema: migration 0069 drops the events table + notes.metadata column +
orphan caldav settings rows (faithful downgrade recreates them).

KEEP: recurrence.py (task recurrence), notifications task reminders, graph
view, and every work surface. Frontend + plugin/docs true-up follow next.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BPtbSzA4JLMAKgFZ8VTg7Q

src/scribe/mcp/tools/recent.py

@@ -1,10 +1,10 @@
 """get_recent — cross-type recent-activity tool.
 
-Returns the most-recently-touched notes, tasks, projects, and events for the
-user, ordered by updated_at descending. Useful for Claude to bootstrap context
-at the start of a conversation ("what was I working on?").
+Returns the most-recently-touched notes, tasks, and projects for the user,
+ordered by updated_at descending. Useful for Claude to bootstrap context at
+the start of a conversation ("what was I working on?").
 
-Aggregation is Python-side after three small per-table queries — simpler than
+Aggregation is Python-side after two small per-table queries — simpler than
 a UNION ALL with type-discriminating columns, and fine for personal-scale data.
 """
 from __future__ import annotations
@@ -15,13 +15,12 @@ from sqlalchemy import select
 
 from scribe.mcp._context import current_user_id
 from scribe.models import async_session
-from scribe.models.event import Event
 from scribe.models.note import Note
 from scribe.models.project import Project
 
 
 async def get_recent(days: int = 7, limit: int = 25) -> dict:
-    """Return recently-touched items across notes, tasks, projects, events.
+    """Return recently-touched items across notes, tasks, and projects.
 
     Args:
         days: Look-back window in days (1-90).
@@ -66,19 +65,6 @@ async def get_recent(days: int = 7, limit: int = 25) -> dict:
                 "title": p.title,
                 "updated_at": p.updated_at.isoformat(),
             })
-        events = (await session.execute(
-            select(Event).where(Event.user_id == uid,
-                                Event.updated_at >= since,
-                                Event.deleted_at.is_(None))
-            .order_by(Event.updated_at.desc()).limit(limit)
-        )).scalars().all()
-        for e in events:
-            items.append({
-                "id": e.id,
-                "type": "event",
-                "title": e.title,
-                "updated_at": e.updated_at.isoformat(),
-            })
     items.sort(key=lambda r: r["updated_at"], reverse=True)
     items = items[:limit]
     return {"items": items, "total": len(items)}