fix(docker): skip husky install in worker runner stage

`pnpm install --frozen-lockfile --prod` runs the package.json `prepare`
script (`husky`) but in --prod mode husky (a devDependency) isn't
installed → "sh: husky: not found" → install fails → Docker build dies.

`ENV HUSKY=0` is husky 9+'s official skip mechanism for CI/Docker
contexts. Adding it before the prod install in Dockerfile.worker.

The main Dockerfile is unaffected because its runner stage copies the
prebuilt `.next/standalone` rather than running pnpm install.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Dockerfile.worker

@@ -29,6 +29,11 @@ WORKDIR /app
 RUN chown -R worker:nodejs /app
 USER worker
 COPY --chown=worker:nodejs package.json pnpm-lock.yaml ./
+# HUSKY=0 skips the husky install during the `prepare` script — husky is a
+# dev dependency so it's not present in --prod installs, and without this
+# guard pnpm install fails with "sh: husky: not found" (husky 9+ honors
+# the HUSKY=0 env var as the official CI/Docker skip mechanism).
+ENV HUSKY=0
 RUN pnpm install --frozen-lockfile --prod
 COPY --from=builder --chown=worker:nodejs /app/dist/worker.js ./worker.js
 # Healthcheck — pings Redis from inside the worker container. Without