Long model names are truncated with ellipsis in two places with no way to see
the full name: the model-picker dropdown items and the chat-header model
indicator. Add a native title tooltip carrying the full name to both — the
dropdown item's name span (nameSpan.title = m.display) and the header label
(label.title = the full model id; empty for the 'Select model' placeholder).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>