Adds word-wrap(text width) — splits strings into lines at word
boundaries respecting terminal width. Rewrites view-chat to:
- Wrap each message with word-wrap before rendering
- Render each wrapped line as a separate add-string call
- Account for wrapped line count in visible-message calculation
RED proof: tmux capture shows messages split mid-word at terminal edge.
GREEN proof: tmux capture shows clean word-boundary wrapping:
The quick brown fox jumps over the lazy dog while the cat naps
peacefully in the sunny garden