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

tests/test_services_dashboard.py

@@ -42,14 +42,12 @@ async def test_build_dashboard_composes_sections():
     import scribe.services.dashboard as dash
     with patch.object(dash, "_active_projects", AsyncMock(return_value=["P"])), \
          patch.object(dash, "_recently_completed", AsyncMock(return_value=["done"])), \
-         patch.object(dash, "_upcoming_events", AsyncMock(return_value=["evt"])), \
          patch.object(dash, "_open_issues", AsyncMock(return_value=["iss"])), \
          patch.object(dash, "_week_stats", AsyncMock(return_value={"open_total": 4})):
         out = await dash.build_dashboard(user_id=1)
     assert out == {
         "active_projects": ["P"],
         "recently_completed": ["done"],
-        "upcoming_events": ["evt"],
         "open_issues": ["iss"],
         "week_stats": {"open_total": 4},
     }
@@ -60,7 +58,6 @@ async def test_build_dashboard_isolates_failing_section():
     import scribe.services.dashboard as dash
     with patch.object(dash, "_active_projects", AsyncMock(side_effect=RuntimeError("db down"))), \
          patch.object(dash, "_recently_completed", AsyncMock(return_value=["done"])), \
-         patch.object(dash, "_upcoming_events", AsyncMock(return_value=[])), \
          patch.object(dash, "_open_issues", AsyncMock(return_value=[])), \
          patch.object(dash, "_week_stats", AsyncMock(return_value={})):
         out = await dash.build_dashboard(user_id=1)