Customer search and detail loads were intermittently slow because every
customer-table render (including each search keystroke) triggered
/monitoring/customers/local-update-status, which looped synchronously over
all customers doing blocking `docker inspect` subprocess calls on the event
loop — stalling all other in-flight requests, including search itself.
- Offload per-service image/container inspection to the thread pool and run
checks concurrently instead of sequentially (image_service, docker_service)
- Reuse a single Docker SDK client instead of reconnecting per customer
- Cache local-update-status results for 20s since the underlying data only
changes after an image pull, not on every keystroke
- Parallelize /monitoring/customers container status lookups
Co-Authored-By: Claude Sonnet 5 <[email protected]>