The provider key was resolved once, at spawn. A provider rejecting it
shows only as an empty end_turn or an idle timeout, neither of which
drops the agent, so a key rotated in the store never reached a running
opencode until the process died for another reason.
After a turn fails with EmptyEndTurn or IdleTimeout, the runtime now
resolves the key once more. When that yields a key that differs from
the one the agent was spawned with, the agent is dropped (SIGINT to its
process group, as every other respawn) and the next turn spawns it with
the new key and reloads the recorded session. No key read (inherited
env value, no store, a failed or timed-out read, nothing stored) keeps
the running agent. The failed turn's error is returned unchanged.
Part of #5017 (slice A).
An opencode ACP agent got its provider API key only from the hand-placed
backendEnvironmentFile. It now also reads it from the swarm secret store
at swarm/agents/<agent>/acp-provider, field api_key, under its own
certificate, and sets it in the spawned ACP agent's environment only.
Nothing is written to disk.
Precedence: a value already in the process environment (the env file)
wins and the store is not asked. Otherwise the stored key is used when
present. With no store, nothing stored, or a failed read, the agent is
spawned without the key as before, and one line is logged without the
value.
The variable name comes from the existing per-agent option
acp.opencode.provider.apiKeyEnv, exported as HIVE_ACP_API_KEY_ENV on the
harness only for the opencode preset. Other ACP commands are unchanged.
The read lives in hive-runtime, where the ACP child is spawned, so both
hive-agent and hive-subagent-daemon use it. The subagent daemon unit
gets the key name and, when the agent has a store, the agent's store
identity (the same credentials queue-identity.nix gives the harness).
No new option or setting. Closes#4841.
