Feature: Add force full-screen refresh command to fix ratatui residual character artifacts #136
Description
Problem Description
When using the TUI, users occasionally experience residual character artifacts on the screen. This happens when:
- Terminal window is resized
- External processes output to the terminal
- Terminal state becomes corrupted
These artifacts are not cleared automatically and can clutter the interface.
Root Cause
The ratatui rendering may not properly invalidate all screen regions in certain edge cases, leaving partial content visible.