feat(tui): Sprint 7 — CJK word-wrap, input history, help, polish
- Replace wrap_line() with unicode-width-aware version (CJK double-width,
hyphen/space/underscore/slash break points, no-break fallback)
- Add input history: Up/Down arrows browse previous inputs, 500-entry cap
with push_history/history_up/history_down methods
- Input history wired in main.rs on message submit
- show_help() renders keybinding reference with Vim-specific section
- 8 new tests: wrap_line (empty, exact, overflow, hyphen, no-break, CJK,
zero-width) + ConversationLine constructors
- 282 tests pass
Sprint 7 of 7 — all sprints complete.
Authored by TheArchitectit
aefd3b23ef