feat(maintenance): guard DB + log growth (Option B + daily prune + rotation)

Root cause of the 2GB prod import.db: the sync_run_orders audit junction
recorded every order on every run; under the 1-minute scheduler ~98% of
21.7M rows were no-op ALREADY_IMPORTED re-observations. NSSM stdout/stderr
also grew unbounded (rotation never applied to the live service).

Changes:
- sqlite_service: skip ALREADY_IMPORTED rows in sync_run_orders (write-side
  guard, _SKIP_JUNCTION_STATUSES); add prune_sync_history(retention_days)
  with incremental_vacuum.
- maintenance_service (new): cleanup_old_logs + run_daily_maintenance.
- scheduler_service: start_maintenance_job (daily CronTrigger).
- main.py: RotatingFileHandler (sync_comenzi_current.log, 10MB x5) instead
  of a new timestamped file per start; schedule daily maintenance + one-shot
  catch-up at startup.
- scripts/db_maintenance.py (new): one-shot prune + VACUUM + log cleanup,
  plain sqlite3, invoked by deploy.ps1 while the service is stopped.
- deploy.ps1: stop -> run db_maintenance.py -> (re)apply NSSM AppRotate*
  idempotently -> start, so rotation reaches pre-existing services.

Retention defaults: 7 days history, 7 days logs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/app/services/scheduler_service.py

@@ -1,6 +1,7 @@
 import logging
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
 from apscheduler.triggers.interval import IntervalTrigger
+from apscheduler.triggers.cron import CronTrigger
 
 logger = logging.getLogger(__name__)
 
@@ -42,6 +43,31 @@ def start_scheduler(interval_minutes: int = 10):
     logger.info(f"Scheduler started with interval {interval_minutes}min")
 
 
+def start_maintenance_job(hour: int = 3):
+    """Schedule the daily DB/log maintenance job (prune history + cleanup logs).
+
+    Runs independently of the sync job — starts the scheduler if it isn't already
+    running so maintenance happens even when auto-sync is disabled.
+    """
+    if _scheduler is None:
+        init_scheduler()
+
+    from . import maintenance_service
+
+    _scheduler.add_job(
+        maintenance_service.run_daily_maintenance,
+        trigger=CronTrigger(hour=hour, minute=0),
+        id="maintenance_job",
+        name="Daily DB/Log Maintenance",
+        replace_existing=True
+    )
+
+    if not _scheduler.running:
+        _scheduler.start()
+
+    logger.info(f"Maintenance job scheduled daily at {hour:02d}:00")
+
+
 def stop_scheduler():
     """Stop the scheduler."""
     global _is_running