fix(deploy): bound service stop so restarts can't hang

systemctl restart was hanging indefinitely: lyra-web's long-lived SSE log
streams block uvicorn's graceful shutdown forever. Add TimeoutStopSec=10 +
KillMode=mixed to both units so stop is bounded (SIGTERM, then SIGKILL the
cgroup) and restart always completes.

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

deploy/lyra-web.service

@@ -8,6 +8,8 @@ UnsetEnvironment=VIRTUAL_ENV
 ExecStart=/home/serversdown/.local/bin/uv run lyra-web
 Restart=on-failure
 RestartSec=5
+TimeoutStopSec=10
+KillMode=mixed
 
 [Install]
 WantedBy=default.target