- Remove height change detection (only width changes trigger full redraw)
- Change clearOnShrink default to false (use PI_CLEAR_ON_SHRINK=1 to enable)
- Fix viewport check to use previousLines.length instead of maxLinesRendered
(prevents false positive redraws when appending lines after content shrunk)
- Add clearOnShrink setting to /settings in coding-agent
- Remove line truncation in custom message component (always show full content)
- Add height change detection (analogous to existing width detection)
- Auto-detect when content shrinks below maxLinesRendered and trigger
full re-render to clear leftover empty rows
- Only triggers when no overlays are active (overlays need padding)
Fixes empty rows appearing below footer when:
- Closing /tree or other selectors
- Clearing multi-line editor content
- Any component shrinking
Also adds regression tests for resize handling and content shrinkage.
