Fix shutdown panic in Docker build

Dockerfile

@@ -10,6 +10,12 @@ ADD https://codeload.github.com/james-6-23/codex2api/tar.gz/refs/heads/main /tmp
 
 RUN tar -xzf /tmp/codex2api.tar.gz --strip-components=1 -C /src
 
+# Upstream currently stops the store twice during shutdown, which causes
+# `panic: close of closed channel` on platforms that send SIGTERM during
+# health/restart cycles. Remove the deferred stop and keep the explicit
+# shutdown path.
+RUN sed -i '/defer store.Stop()/d' /src/main.go
+
 FROM node:20-alpine AS frontend-builder
 
 WORKDIR /frontend