Fix screen redraw issue in terminal reader

[jwalsh]

The terminal-based Proust reader has a screen redraw issue that can cause flickering when moving between paragraphs or when the window size changes.

Steps to reproduce:

1. Run the proust_reader without --ast flag
2. Observe the display while reading progresses between paragraphs
3. Try resizing the terminal window

Expected behavior:

• Smooth scrolling between paragraphs
• Clean redraw when window size changes
• No visible flickering or artifacts

Potential solutions:

• Use curses pad objects instead of direct window drawing
• Implement double-buffering for the display
• Add smart refresh that only updates changed areas
• Add window size change detection and proper handling

This improvement will enhance the user experience for the terminal reader component.