* chore: Add cors to workspace proxies to allow for latency checks
* Add latency check to wsproxy
Use performance API timings.
- Fix cors and timing headers
- Accept custom headers
* chore: Implement workspace proxy going away
When a workspace proxy shuts down, the health status of that
proxy should immediately be updated. This is purely a courtesy
and technically not required
* chore: Implement workspace proxy health check cron
At a given interval will check the reachability of workspace proxies.
* Proxyhealth is an enterprise feature
* Start proxyhealth go routine on enterprise coder
