Bug Description

Isolated cron jobs with delivery: { mode: "announce", channel: "telegram", to: "..." } complete successfully (lastStatus: "ok") but fail to deliver their output message to the configured channel.

Steps to Reproduce

1. Create an isolated cron job with delivery.announce:

{
  "schedule": { "kind": "cron", "expr": "30 7 * * *" },
  "sessionTarget": "isolated",
  "payload": { "kind": "agentTurn", "message": "Generate summary..." },
  "delivery": { "mode": "announce", "channel": "telegram", "to": "..." }
}

2. Wait for cron to trigger
3. Check isolated session history - task completes successfully
4. Check Telegram - no message received

Expected Behavior

The final assistant reply from the isolated session should be delivered to the specified Telegram channel/user.

Actual Behavior

• Isolated session completes with stopReason: "stop"
• Cron reports lastStatus: "ok"
• Message is never delivered to Telegram
• No error logged

Workaround

None currently - considering switching to main session systemEvent target, but that defeats the purpose of isolated sessions for background work.

Environment

• OpenClaw: latest
• Channel: Telegram
• Platform: macOS (Darwin 25.2.0 arm64)
• Node: v24.12.0