feat(journal): backend services (moments, search, prep, scheduler, pipeline)

- services/moments.py — CRUD with embedding sync + entity-link helpers
- services/journal_search.py — three-mode search (temporal / entity / semantic)
  with notes-RAG isolation; cosine-similarity helper unit-tested
- services/journal_prep.py — gathers tasks/events/weather/news/projects/
  recent-moments/open-threads into a structured prep block
- services/journal_scheduler.py — per-user APScheduler cron for daily prep,
  follows the BackgroundScheduler + threadsafe-async pattern from event_scheduler
- services/journal_pipeline.py — system prompt (persona + calibration rules)
  with last-48h ambient moments injection
- app.py: wire journal scheduler start/stop hooks
- routes/settings.py: re-add live-reschedule on timezone change (now via
  journal_scheduler.update_user_schedule)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/fabledassistant/app.py

@@ -331,7 +331,9 @@ def create_app() -> Quart:
 
         asyncio.create_task(_delayed_backfill())
 
-        # Journal scheduler is wired up in Stage C (services/journal_scheduler).
+        # Start journal scheduler (per-user daily prep generation)
+        from fabledassistant.services.journal_scheduler import start_journal_scheduler
+        start_journal_scheduler(asyncio.get_running_loop())
 
         # Start event scheduler (reminders + CalDAV pull sync)
         from fabledassistant.services.event_scheduler import start_event_scheduler
@@ -345,6 +347,8 @@ def create_app() -> Quart:
 
     @app.after_serving
     async def shutdown():
+        from fabledassistant.services.journal_scheduler import stop_journal_scheduler
+        stop_journal_scheduler()
         from fabledassistant.services.event_scheduler import stop_event_scheduler
         stop_event_scheduler()