* feat(commands): add /rename command to set a custom session title
Adds a `/rename <new title>` slash command that lets users set a
human-readable name for the current session. The new title is
persisted immediately to the session JSON file so it appears in
the session picker on the next open.
- Max title length capped at 100 characters (char-count aware, handles CJK)
- Errors on missing/empty arg or no active session
- Inner `rename_with_manager` helper keeps unit tests fully isolated
from ~/.deepseek/sessions
- Localized descriptions in en, ja, zh-Hans, pt-BR
* fix(rename): sync App state before saving to prevent data loss
Use update_session() to merge current in-memory messages and tokens
into the session before writing the renamed title, preventing stale
disk data from overwriting unsaved App state.
* style: format rename command
---------
Co-authored-by: Hunter Bown <hmbown@gmail.com>
kitty
719594636c