Preserve opened subagents when parents are archived (#3279)

* fix(subagents): preserve opened children on parent archive

Opening a managed child represents user ownership only while that client's tab remains open. Track that intent per client, detach surviving children during parent archive, and keep single and bulk tab-close behavior consistent.

* fix(subagents): mark generic tab openings

Centralize managed child tab ownership in agent navigation so list, command-center, deep-link, notification, and subagent-track openings all mark ownership before creating the tab. Use stable localized errors for lifecycle failures.

* fix(subagents): classify cold tab openings

Fetch uncached agents before deciding whether tab ownership must be recorded, so notification, desktop, and cold-route openings cannot bypass parent archive protection.

* fix(app): translate navigation fallback errors

* fix(navigation): allow offline workspace intents

* refactor(app): derive subagent ownership from open tabs

* fix(server): serialize subagent lifecycle ownership

packages/app/src/i18n/resources/ar.ts

@@ -614,6 +614,7 @@ export const ar: TranslationResources = {
         reloadingAgent: "وكيل إعادة التحميل...",
         reloadedAgent: "وكيل إعادة تحميل",
         failedToReloadAgent: "فشل في إعادة تحميل الوكيل",
+        failedToCloseAgent: "فشل في إغلاق الوكيل",
       },
       confirmations: {
         unsavedTitle: "تغييرات غير محفوظة",