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>

src/infra/heartbeat-runner.respects-ackmaxchars-heartbeat-acks.test.ts

@@ -483,6 +483,80 @@ describe("resolveHeartbeatIntervalMs", () => {
     }
   });
 
+  it("uses explicit heartbeat accountId for telegram delivery", async () => {
+    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-hb-"));
+    const storePath = path.join(tmpDir, "sessions.json");
+    const replySpy = vi.spyOn(replyModule, "getReplyFromConfig");
+    const prevTelegramToken = process.env.TELEGRAM_BOT_TOKEN;
+    process.env.TELEGRAM_BOT_TOKEN = "";
+    try {
+      const cfg: OpenClawConfig = {
+        agents: {
+          defaults: {
+            workspace: tmpDir,
+            heartbeat: { every: "5m", target: "telegram", accountId: "work" },
+          },
+        },
+        channels: {
+          telegram: {
+            accounts: {
+              work: { botToken: "test-bot-token-123" },
+            },
+          },
+        },
+        session: { store: storePath },
+      };
+      const sessionKey = resolveMainSessionKey(cfg);
+
+      await fs.writeFile(
+        storePath,
+        JSON.stringify(
+          {
+            [sessionKey]: {
+              sessionId: "sid",
+              updatedAt: Date.now(),
+              lastChannel: "telegram",
+              lastProvider: "telegram",
+              lastTo: "123456",
+            },
+          },
+          null,
+          2,
+        ),
+      );
+
+      replySpy.mockResolvedValue({ text: "Hello from heartbeat" });
+      const sendTelegram = vi.fn().mockResolvedValue({
+        messageId: "m1",
+        chatId: "123456",
+      });
+
+      await runHeartbeatOnce({
+        cfg,
+        deps: {
+          sendTelegram,
+          getQueueSize: () => 0,
+          nowMs: () => 0,
+        },
+      });
+
+      expect(sendTelegram).toHaveBeenCalledTimes(1);
+      expect(sendTelegram).toHaveBeenCalledWith(
+        "123456",
+        "Hello from heartbeat",
+        expect.objectContaining({ accountId: "work", verbose: false }),
+      );
+    } finally {
+      replySpy.mockRestore();
+      if (prevTelegramToken === undefined) {
+        delete process.env.TELEGRAM_BOT_TOKEN;
+      } else {
+        process.env.TELEGRAM_BOT_TOKEN = prevTelegramToken;
+      }
+      await fs.rm(tmpDir, { recursive: true, force: true });
+    }
+  });
+
   it("does not pre-resolve telegram accountId (allows config-only account tokens)", async () => {
     const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-hb-"));
     const storePath = path.join(tmpDir, "sessions.json");