Nine subtests covering the poll loop, pubsub notification path,
timeout, context cancellation, descendant auth check, and both
error-status branches in handleSubagentDone.
Wire p.clock through awaitSubagentCompletion's timer and ticker
so future tests can use quartz mock clock. Tests use channel-based
coordination and context.WithTimeout instead of time.Sleep.
Coverage: awaitSubagentCompletion 0%->70.3%, handleSubagentDone
0%->100%, checkSubagentCompletion 0%->77.8%,
latestSubagentAssistantMessage 0%->78.9%.
- Moves `coderd/chatd/`, `coderd/gitsync/`, `enterprise/coderd/chatd/`
under `x/` parent directories to signal instability
- Adds `Experimental:` glue code comments in `coderd/coderd.go`
> 🤖 This PR was created with the help of Coder Agents, and was
reviewed by my human. 🧑💻
Mathias Fredriksson