vm.go: Firecracker was launched with context.Background() instead of
the incoming request ctx. A cancelled or timed-out VM creation request
could not stop mid-flight Firecracker process spawning, leaving an
orphaned process and leaked resources. Replace the four firecrackerCtx
uses with ctx directly; the local variable is removed.
guest_sessions.go / daemon.go: sessionControllers map was lazily
initialized with a nil-check inside every mutating method. With d.mu
held this isn't a data race, but the pattern is fragile — any new
method that writes to the map without copying the guard can panic.
Initialize the map once in Open() alongside the other daemon maps and
channels, and remove the redundant nil-checks from setGuestSessionController
and claimGuestSessionController.