feat(avatar): add private vision chat support

digital-avatar-app/backend/main.py

@@ -19,11 +19,13 @@ import routers.huihui_auth
 import routers.chat
 import routers.takeover
 from responses import ok
+from services.chat_attachment_service import purge_expired_chat_attachments
 from services.token_billing import DEFAULT_TOKEN_GRANT, release_stale_reservations
 
 logger = logging.getLogger(__name__)
 
 takeover_scheduler = None
+maintenance_scheduler = None
 
 app = FastAPI(title="会会数字分身 API", version="1.0.0")
 
@@ -132,6 +134,15 @@ def on_startup():
 
     # Release stale resources when startup is invoked again by a reload/test.
     stop_takeover_scheduler()
+    stop_maintenance_scheduler()
+    try:
+        start_maintenance_scheduler()
+    except Exception as exc:
+        stop_maintenance_scheduler()
+        logger.warning(
+            "Failed to initialize chat attachment cleanup, app will continue: %s",
+            exc,
+        )
 
     # --- Takeover scheduler ---
     try:
@@ -196,6 +207,51 @@ def stop_takeover_scheduler():
         finally:
             takeover_scheduler = None
 
+
+def purge_expired_chat_attachments_job():
+    db = SessionLocal()
+    try:
+        count = purge_expired_chat_attachments(db)
+        if count:
+            logger.info("Purged %s expired chat image attachment(s)", count)
+    except Exception as exc:
+        db.rollback()
+        logger.warning("Failed to purge expired chat image attachments: %s", exc)
+    finally:
+        db.close()
+
+
+def start_maintenance_scheduler():
+    global maintenance_scheduler
+
+    purge_expired_chat_attachments_job()
+    interval_minutes = max(
+        5, min(1440, int(os.getenv("CHAT_ATTACHMENT_CLEANUP_MINUTES", "60")))
+    )
+    maintenance_scheduler = AsyncIOScheduler()
+    maintenance_scheduler.add_job(
+        purge_expired_chat_attachments_job,
+        trigger=IntervalTrigger(minutes=interval_minutes),
+        id="chat_attachment_cleanup",
+        max_instances=1,
+        coalesce=True,
+    )
+    maintenance_scheduler.start()
+
+
+def stop_maintenance_scheduler():
+    global maintenance_scheduler
+
+    if maintenance_scheduler is not None:
+        try:
+            if maintenance_scheduler.running:
+                maintenance_scheduler.shutdown(wait=False)
+        except Exception as exc:
+            logger.warning("Failed to stop maintenance scheduler cleanly: %s", exc)
+        finally:
+            maintenance_scheduler = None
+
 @app.on_event("shutdown")
 def on_shutdown():
     stop_takeover_scheduler()
+    stop_maintenance_scheduler()