Allow renaming terminal tabs

[germanescobar]

Summary

Add support for renaming terminal tabs within a worktree.

Current behavior

Terminal tabs are automatically labeled, for example Terminal 1 and Terminal 2, and users cannot change those labels.

Desired behavior

Users should be able to rename each terminal tab so they can identify long-running tasks or shell contexts more easily, for example Server, Tests, or DB console.

Suggested implementation notes

• Add an inline rename affordance or menu action on each terminal tab.
• Persist custom labels in the existing per-project/worktree terminal tab metadata in localStorage.
• Keep stable terminalId values unchanged when labels change.
• Validate labels enough to avoid empty or excessively long tab names.
• Ensure renamed labels restore after browser refresh.

Acceptance criteria

• A user can rename a terminal tab.
• Renaming a tab does not restart or replace its PTY.
• Custom names persist after refresh for the same project/worktree.
• Empty names are rejected or normalized back to the previous/default label.
• The existing auto-generated tab labels remain the default for new terminals.