feat(tui): clean transcript style, right-click context menus, rate limits & dual copy
- Add clean line-by-line transcript style toggle ('b' key / /clean / /boxed)
- Implement right-click context menus for chat list, fleet agent panel, and transcript
- Add cooldown mode lock bypass (2-second double-confirm force sync)
- Implement dual copy support: clean text (strip reply metadata) vs full context
- Add clickable [📋 Copy] and [📑+ Context] buttons to message headers
- Add unit test suites for transcript cleaning, context menus, rate limits, and copy actions
operator
b7e45010c3