* 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
