feat(heartbeat): add accountId config option for multi-agent routing (#8702)

* feat(heartbeat): add accountId config option for multi-agent routing

Add optional accountId field to heartbeat configuration, allowing
multi-agent setups to explicitly specify which Telegram account
should be used for heartbeat delivery.

Previously, heartbeat delivery would use the accountId from the
session's deliveryContext. When a session had no prior conversation
history, heartbeats would default to the first/primary account
instead of the agent's intended bot.

Changes:
- Add accountId to HeartbeatSchema (zod-schema.agent-runtime.ts)
- Use heartbeat.accountId with fallback to session accountId (targets.ts)

Backward compatible: if accountId is not specified, behavior is unchanged.

Closes #8695

* fix: improve heartbeat accountId routing (#8702) (thanks @lsh411)

* fix: harden heartbeat accountId routing (#8702) (thanks @lsh411)

* fix: expose heartbeat accountId in status (#8702) (thanks @lsh411)

* chore: format status + heartbeat tests (#8702) (thanks @lsh411)

---------

Co-authored-by: m1 16 512 <m116512@m1ui-MacBookAir-2.local>
Co-authored-by: Gustavo Madeira Santana <gumadeiras@gmail.com>

CHANGELOG.md

@@ -20,6 +20,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Heartbeat: allow explicit accountId routing for multi-account channels. (#8702) Thanks @lsh411.
 - Shell completion: auto-detect and migrate slow dynamic patterns to cached files for faster terminal startup; add completion health checks to doctor/update/onboard.
 - Telegram: honor session model overrides in inline model selection. (#8193) Thanks @gildo.
 - Web UI: fix agent model selection saves for default/non-default agents and wrap long workspace paths. Thanks @Takhoffman.