fix: Prevent key buffering during rate limiting

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

main.py

@@ -43,12 +43,12 @@ def main_loop(stdscr):
     logging.info('Starting main loop...')
 
     while True:
-        # Rate limit key presses unless in a text input field
-        if not screens[state.current_screen].is_typing and time.time() < state.last_key_time + 1:
-            time.sleep(0.05)
-        else:
         c = stdscr.getch()
         if c != curses.ERR:
+            # Rate limit key presses unless in a text input field
+            if not screens[state.current_screen].is_typing and time.time() < state.last_key_time + 1:
+                pass  # Key press ignored due to rate limit
+            else:
                 state.c = c
                 state.last_key_time = time.time()
                 screens[state.current_screen].handle_input(c)