feat: reintegrate MCP server with proper session manager lifecycle, nginx /mcp proxy, docker.sock mount

backend/app/main.py

@@ -11,6 +11,7 @@ from app.cache import cache
 from app.routers import equipment, health, admin, rental_requests, contact
 from app.services.sync_service import SyncService
 from app.services.email_service import EmailService
+from app.mcp_server import get_mcp_app, mcp_session_manager
 
 logger = logging.getLogger(__name__)
 settings = get_settings()
@@ -41,6 +42,9 @@ async def lifespan(app: FastAPI):
     await init_db()
     await cache.connect()
 
+    _mcp_cm = mcp_session_manager.run()
+    await _mcp_cm.__aenter__()
+
     scheduler.add_job(run_equipment_sync, trigger="cron", hour="*/6", id="equipment_sync", replace_existing=True)
     scheduler.add_job(run_email_retry, trigger="cron", minute="*/15", id="email_retry", replace_existing=True)
     scheduler.start()
@@ -49,6 +53,7 @@ async def lifespan(app: FastAPI):
     yield
 
     scheduler.shutdown(wait=False)
+    await _mcp_cm.__aexit__(None, None, None)
     await cache.disconnect()
     await engine.dispose()
 
@@ -63,3 +68,5 @@ app.include_router(health.router)
 app.include_router(admin.router)
 app.include_router(rental_requests.router)
 app.include_router(contact.router)
+
+app.mount("/mcp", get_mcp_app())