Daemon no longer owns a coarse mu shared across unrelated concerns.
Each subsystem now carries its own state and lock:
- tapPool: entries, next, and mu move onto a new tapPool struct.
- sessionRegistry: sessionControllers + its mutex move off Daemon.
- opRegistry[T asyncOp]: generic registry collapses the two ad-hoc
vm-create and image-build operation maps (and their mutexes) into one
shared type; the Begin/Status/Cancel/Prune methods simplify.
- vmLockSet: the sync.Map of per-VM mutexes moves into its own type;
lockVMID forwards.
- Daemon.mu splits into imageOpsMu (image-registry mutations) and
createVMMu (CreateVM serialisation) so image ops and VM creates no
longer block each other.
Lock ordering collapses to vmLocks[id] -> {createVMMu, imageOpsMu} ->
subsystem-local leaves. doc.go and ARCHITECTURE.md updated.
No behavior change; tests green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
