When a webhook or cron job provides a stable sessionKey, the session
should maintain conversation history across invocations. Previously,
resolveCronSession always generated a new sessionId and hardcoded
isNewSession: true, preventing any conversation continuity.
Changes:
- Check if existing entry has a valid sessionId
- Evaluate freshness using configured reset policy
- Reuse sessionId and set isNewSession: false when fresh
- Add forceNew parameter to override reuse behavior
- Spread existing entry to preserve conversation context
This enables persistent, stateful conversations for webhook-driven
agent endpoints when allowRequestSessionKey is configured.
Fixes#18027
57c8f62396