feat(cron): add failure destination support to failed cron jobs (#31059)

* feat(cron): add failure destination support with webhook mode and bestEffort handling

Extends PR #24789 failure alerts with features from PR #29145:
- Add webhook delivery mode for failure alerts (mode: 'webhook')
- Add accountId support for multi-account channel configurations
- Add bestEffort handling to skip alerts when job has bestEffort=true
- Add separate failureDestination config (global + per-job in delivery)
- Add duplicate prevention (prevents sending to same as primary delivery)
- Add CLI flags: --failure-alert-mode, --failure-alert-account-id
- Add UI fields for new options in web cron editor

* fix(cron): merge failureAlert mode/accountId and preserve failureDestination on updates

- Fix mergeCronFailureAlert to merge mode and accountId fields
- Fix mergeCronDelivery to preserve failureDestination on updates
- Fix isSameDeliveryTarget to use 'announce' as default instead of 'none'
  to properly detect duplicates when delivery.mode is undefined

* fix(cron): validate webhook mode requires URL in resolveFailureDestination

When mode is 'webhook' but no 'to' URL is provided, return null
instead of creating an invalid plan that silently fails later.

* fix(cron): fail closed on webhook mode without URL and make failureDestination fields clearable

- sendCronFailureAlert: fail closed when mode is webhook but URL is missing
- mergeCronDelivery: use per-key presence checks so callers can clear
  nested failureDestination fields via cron.update

Note: protocol:check shows missing internalEvents in Swift models - this is
a pre-existing issue unrelated to these changes (upstream sync needed).

* fix(cron): use separate schema for failureDestination and fix type cast

- Create CronFailureDestinationSchema excluding after/cooldownMs fields
- Fix type cast in sendFailureNotificationAnnounce to use CronMessageChannel

* fix(cron): merge global failureDestination with partial job overrides

When job has partial failureDestination config, fall back to global
config for unset fields instead of treating it as a full override.

* fix(cron): avoid forcing announce mode and clear inherited to on mode change

- UI: only include mode in patch if explicitly set to non-default
- delivery.ts: clear inherited 'to' when job overrides mode, since URL
  semantics differ between announce and webhook modes

* fix(cron): preserve explicit to on mode override and always include mode in UI patches

- delivery.ts: preserve job-level explicit 'to' when overriding mode
- UI: always include mode in failureAlert patch so users can switch between announce/webhook

* fix(cron): allow clearing accountId and treat undefined global mode as announce

- UI: always include accountId in patch so users can clear it
- delivery.ts: treat undefined global mode as announce when comparing for clearing inherited 'to'

* Cron: harden failure destination routing and add regression coverage

* Cron: resolve failure destination review feedback

* Cron: drop unrelated timeout assertions from conflict resolution

* Cron: format cron CLI regression test

* Cron: align gateway cron test mock types

---------

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

src/cli/cron-cli.test.ts

@@ -679,19 +679,39 @@ describe("cron cli", () => {
     expect(patch?.patch?.failureAlert).toBe(false);
   });
 
-  it("uses a longer default timeout for cron run", async () => {
-    const { runOpts } = await runCronRunAndCaptureExit({
-      ran: true,
-      args: ["cron", "run", "job-1", "--expect-final"],
-    });
-    expect(runOpts.timeout).toBe("600000");
-  });
+  it("patches failure alert mode/accountId on cron edit", async () => {
+    callGatewayFromCli.mockClear();
 
-  it("preserves explicit --timeout for cron run", async () => {
-    const { runOpts } = await runCronRunAndCaptureExit({
-      ran: true,
-      args: ["cron", "run", "job-1", "--expect-final", "--timeout", "45000"],
-    });
-    expect(runOpts.timeout).toBe("45000");
+    const program = buildProgram();
+
+    await program.parseAsync(
+      [
+        "cron",
+        "edit",
+        "job-1",
+        "--failure-alert-after",
+        "1",
+        "--failure-alert-mode",
+        "webhook",
+        "--failure-alert-account-id",
+        "bot-a",
+      ],
+      { from: "user" },
+    );
+
+    const updateCall = callGatewayFromCli.mock.calls.find((call) => call[0] === "cron.update");
+    const patch = updateCall?.[2] as {
+      patch?: {
+        failureAlert?: {
+          after?: number;
+          mode?: "announce" | "webhook";
+          accountId?: string;
+        };
+      };
+    };
+
+    expect(patch?.patch?.failureAlert?.after).toBe(1);
+    expect(patch?.patch?.failureAlert?.mode).toBe("webhook");
+    expect(patch?.patch?.failureAlert?.accountId).toBe("bot-a");
   });
 });