Add Settle + new thread to thread actions

[PookMook]

Problem

After finishing a thread, I usually want to settle it and immediately start the next one in the same place.

Today these are separate actions: settle the finished thread, open New task, then select the relevant environment and project again.

The missing menu item here is Settle + new thread. The Rust + Solid rewrite is, naturally, for the memes.

Proposal

Add Settle + new thread next to Settle in the thread action menu on mobile and web/desktop.

On an idle, settleable thread it would:

1. Settle the current thread.
2. Open a blank new-thread draft for the same environment and project.
3. Use the normal new-thread defaults for provider, model, mode, and worktree behavior.
4. Focus the composer.

If settling fails, stay on the current thread. If the thread is still running or has unresolved work, disable the action under the same rules as ordinary settlement.

This should not copy conversation context, create a handoff, or automatically send a prompt. It is only a shortcut from a completed thread to a blank new one.

Would this small cross-client action fit T3 Code?