fix(cron): pass heartbeat target=last for main-session cron jobs (#28508) (#28583)

* fix(cron): pass heartbeat target=last for main-session cron jobs

When a cron job with sessionTarget=main and wakeMode=now fires, it
triggers a heartbeat via runHeartbeatOnce. Since e2362d35 changed the
default heartbeat target from "last" to "none", these cron-triggered
heartbeats silently discard their responses instead of delivering them
to the last active channel (e.g. Telegram).

Fix: pass heartbeat: { target: "last" } from the cron timer to
runHeartbeatOnce for main-session jobs, and wire the override through
the gateway cron service builder. This restores delivery for
sessionTarget=main cron jobs without reverting the intentional default
change for regular heartbeats.

Regression introduced in: e2362d35 (2026-02-25)

Fixes #28508

* Cron: align server-cron wake routing expectations for main-target jobs

---------

Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/cron/service/timer.ts

@@ -663,6 +663,11 @@ export async function executeJobCore(
           reason,
           agentId: job.agentId,
           sessionKey: targetMainSessionKey,
+          // Cron-triggered heartbeats should deliver to the last active channel.
+          // Without this override, heartbeat target defaults to "none" (since
+          // e2362d35) and cron main-session responses are silently swallowed.
+          // See: https://github.com/openclaw/openclaw/issues/28508
+          heartbeat: { target: "last" },
         });
         if (
           heartbeatResult.status !== "skipped" ||