We're doing this internally for agents, but we need it also on the deployment level too.

Health section progress:

• Access URL is validfeat(healthcheck): add accessurl check #7193
• DERPfeat(coderd): add DERP healthcheck #6936
• Websocket supportfeat(healthcheck): add websocket report #7689
• Format the JSON response so that it's more human-readable until we have a proper frontendfeat: format healthcheck responses #7723
• HA/Replica issues