The 'do not poll/sleep' note added to sessions_spawn tool results causes
cron isolated agents to immediately end their turn, since the note tells
them not to wait for subagent results. In cron isolated sessions, the
agent turn IS the entire run, so ending early means subagent results
are never collected.
Fix: detect cron sessions via includes(':cron:') in agentSessionKey
and suppress the note, allowing the agent to poll/wait naturally.
Note: PR #27330 used startsWith('cron:') which never matches because
the session key format is 'agent:main:cron:...' (starts with 'agent:').
Fixes#27308Fixes#25069
