Thinking selector fix:
- Replace hardcoded 50-character borders with DynamicBorder component
that adjusts to viewport width
- Prevents crash when terminal is resized narrow
Text/Markdown rendering fixes:
- Fix Markdown wrapSingleLine to check if adding next character would
exceed width BEFORE adding it (was checking AFTER, causing lines to
be 1 character too long)
- Add word truncation in Text component for words longer than
contentWidth (prevents long unbreakable words from exceeding width)
These fixes prevent "Rendered line exceeds terminal width" errors.
02a21dd936