Logs now say why a subagent transcript could not be resumed instead of just "not found".
What's wrong with this entry?
When a sub-agent transcript cannot be resumed, the logs now distinguish a missing transcript, one the storage layer refused for permission reasons, and an outright error, instead of a bare "not found".
- Results are also tagged with how they were served, so a cached load can be told apart from a fresh one.
getAgentTranscript: the storage backend cannot serve this agent transcript (permission); not resumable
Strings lifted out of the shipped bundle, so the claim above can be checked against them.