This PR introduces the only wakeBuffer clear at the ACP startTurn site, and it
also clears midTurnUnreportedCompletedTaskIds there, both on the reasoning that
a user turn owns the conversation.

An orchestrator-injected wake is not a user turn. #4499
fix/delegated-task-parent-wake dispatches app-owned delegated-child wakes as
creationSource "server", which is non-continuation, so once both land such a
wake would discard this session's pending native wake frames and its kept
mid-turn completion marks, losing agent output and a continuation offer that
nothing else can recover.

acpIsAppOwnedWakeTurn exempts orchestrator-injected wakes from both clears,
matching what ClaudeAdapterV2 already does with its own buffer. Inert without
#4499, since nothing else dispatches creationSource "server". Kept as its own
commit because the concern originates in a different PR.