refactor: Remove scrollbar change markers and related code

gtm

@@ -330,34 +330,6 @@ def jump_to_prev_change(state: AppState) -> AppState:
         return replace(state, right_scroll_offset=new_scroll, current_change_idx=prev_idx)
     return state
 
-def draw_change_markers(stdscr, state):
-    """Draw markers in the scrollbar area to indicate where changes are located."""
-    if not state.change_blocks or not (state.show_whole_diff or state.show_additions or state.show_deletions):
-        return
-    
-    right_start = 0 if not state.show_sidebar else state.divider_col + 2
-    right_width = state.width - right_start - 1
-    marker_col = right_start + right_width - 1
-    
-    # Calculate scaling factor for marker positions
-    total_lines = len(state.file_lines)
-    if total_lines <= 1:
-        return
-    
-    scale_factor = (state.height - 1) / total_lines
-    
-    # Draw markers
-    for i, (start_pos, _) in enumerate(state.change_blocks):
-        marker_y = int(start_pos * scale_factor)
-        if 0 <= marker_y < state.height - 1:
-            # Use a single color for change blocks
-            attr = curses.color_pair(5)  # New color pair for change blocks
-            marker_char = '>' if i == state.current_change_idx else '|'
-            
-            try:
-                stdscr.addch(marker_y, marker_col, marker_char, attr)
-            except curses.error:
-                pass
 
 def draw_right_pane(stdscr, state):
     # If sidebar is hidden, right pane starts at column 0
@@ -615,9 +587,6 @@ def draw_ui(stdscr, state):
     draw_left_pane(stdscr, state)
     draw_right_pane(stdscr, state)
     draw_divider(stdscr, state)
-    # Only draw change markers in the right pane
-    if state.focus == "right":
-        draw_change_markers(stdscr, state)
     draw_status_bars(stdscr, state)
     draw_selection(stdscr, state)
     stdscr.refresh()
@@ -820,7 +789,6 @@ def main(stdscr, filename, show_diff, show_add, show_del, mouse, wrap_lines=True
         curses.init_pair(2, curses.COLOR_WHITE, 0)  # Inactive pane: white on black
         curses.init_pair(3, curses.COLOR_GREEN, -1)  # Added lines
         curses.init_pair(4, curses.COLOR_RED, -1)    # Deleted lines
-        curses.init_pair(5, curses.COLOR_YELLOW, -1) # Change block markers
 
     height, width = stdscr.getmaxyx()
     state = AppState(