Enhanced Wide Character Rendering

What: Improved handling of emoji and CJK characters in terminal output through explicit width tracking in the screen buffer.

Details:

• Cell objects now include explicit width property (0 for normal, 1 for wide, 2/3 for placeholder)
• Automatic insertion of placeholder cells when writing wide characters
• Renderer skips placeholder cells to prevent double-rendering artifacts
• Width-aware cursor movement (advances 2 positions for wide characters)
• Fixes rendering bugs where placeholder cells were processed incorrectly
• Evidence: Enhanced cell type pf9 at line 67236, width-aware write function $P0() at line 67208, placeholder skipping logic at lines 67852-67853 in pretty-v2.0.34.js