feat(cron): add --account flag for multi-account delivery routing (#26284)

* feat(cron): add --account flag for multi-account delivery routing

Add support for explicit delivery account routing in cron jobs across CLI, normalization, delivery planning, and isolated delivery target resolution.

Highlights:
- Add --account <id> to cron add and cron edit
- Add optional delivery.accountId to cron types and delivery plan
- Normalize and trim delivery.accountId in cron create/update normalization
- Prefer explicit accountId over session lastAccountId and bindings fallback
- Thread accountId through isolated cron run delivery resolution
- Preserve cron edit --best-effort-deliver/--no-best-effort-deliver behavior by keeping implicit announce mode
- Expand tests for account passthrough/merge/precedence and CLI account flows

* cron: resolve rebase duplicate accountId fields

---------

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

src/cron/normalize.test.ts

@@ -212,6 +212,51 @@ describe("normalizeCronJobCreate", () => {
     expect(delivery.to).toBe("7200373102");
   });
 
+  it("normalizes delivery accountId and strips blanks", () => {
+    const normalized = normalizeCronJobCreate({
+      name: "delivery account",
+      enabled: true,
+      schedule: { kind: "cron", expr: "* * * * *" },
+      sessionTarget: "isolated",
+      wakeMode: "now",
+      payload: {
+        kind: "agentTurn",
+        message: "hi",
+      },
+      delivery: {
+        mode: "announce",
+        channel: "telegram",
+        to: "-1003816714067",
+        accountId: " coordinator ",
+      },
+    }) as unknown as Record<string, unknown>;
+
+    const delivery = normalized.delivery as Record<string, unknown>;
+    expect(delivery.accountId).toBe("coordinator");
+  });
+
+  it("strips empty accountId from delivery", () => {
+    const normalized = normalizeCronJobCreate({
+      name: "empty account",
+      enabled: true,
+      schedule: { kind: "cron", expr: "* * * * *" },
+      sessionTarget: "isolated",
+      wakeMode: "now",
+      payload: {
+        kind: "agentTurn",
+        message: "hi",
+      },
+      delivery: {
+        mode: "announce",
+        channel: "telegram",
+        accountId: "   ",
+      },
+    }) as unknown as Record<string, unknown>;
+
+    const delivery = normalized.delivery as Record<string, unknown>;
+    expect("accountId" in delivery).toBe(false);
+  });
+
   it("normalizes webhook delivery mode and target URL", () => {
     const normalized = normalizeCronJobCreate({
       name: "webhook delivery",