fix: riscrivi TerminalUI piu semplice e robusto

- Usa output_buffer per scrollback manuale
- Non usa pty/select complessi
- Piu stabile su terminali diversi

langcode.py

@@ -111,14 +111,8 @@ def cmd_chat(args):
         
         if use_terminal:
             try:
-                import shutil
-                rows = min(40, shutil.get_terminal_size().lines)
-                columns = min(120, shutil.get_terminal_size().columns)
-                
                 from terminal_ui import create_terminal_ui
                 term = create_terminal_ui(
-                    rows=rows,
-                    columns=columns,
                     scrollback=10000,
                     prompt="❯ "
                 )