fix: Prevent last file lines from being hidden by status bar

gtm

@@ -361,13 +361,21 @@ def page_commit_selection(state: AppState, direction: int) -> AppState:
     return move_commit_selection(state, delta)
 
 def scroll_right_pane(state: AppState, delta: int) -> AppState:
-    max_scroll = max(0, len(state.file_lines) - (state.height - 1))
+    # Calculate visible height accounting for status bar
+    visible_height = state.height - state.status_bar_height
+    
+    # Calculate maximum scroll position
+    max_scroll = max(0, len(state.file_lines) - visible_height)
+    
+    # Apply scroll delta and clamp to valid range
     new_offset = state.right_scroll_offset + delta
     new_offset = max(0, min(new_offset, max_scroll))
+    
     return replace(state, right_scroll_offset=new_offset)
 
 def page_right_pane(state: AppState, direction: int) -> AppState:
-    page_size = state.height - 1
+    # Calculate page size accounting for status bar
+    page_size = state.height - state.status_bar_height
     delta = page_size * direction
     return scroll_right_pane(state, delta)
 
@@ -538,10 +546,15 @@ def draw_right_pane(stdscr, state):
     
     right_width = state.width - right_start - 1
     
-    max_scroll = max(0, len(state.file_lines) - (state.height - state.status_bar_height))
+    # Calculate the visible height (accounting for status bar)
+    visible_height = state.height - state.status_bar_height
+    
+    # Calculate maximum scroll position
+    max_scroll = max(0, len(state.file_lines) - visible_height)
     state.right_scroll_offset = min(state.right_scroll_offset, max_scroll)
     
-    visible_lines = state.file_lines[state.right_scroll_offset:state.right_scroll_offset + state.height - state.status_bar_height]
+    # Get visible lines based on the calculated visible height
+    visible_lines = state.file_lines[state.right_scroll_offset:state.right_scroll_offset + visible_height]
 
     display_lines = []
     deleted_line_map = {}
@@ -1213,6 +1226,10 @@ def update_status_bar_height(state: AppState, my: int) -> AppState:
     # Clamp to allowed range
     new_height = max(min_height, min(new_height, max_height))
     
+    # Ensure we're not hiding too much content
+    content_height = max(state.height - new_height, 5)  # At least 5 lines for content
+    new_height = min(new_height, state.height - content_height)
+    
     return replace(state, status_bar_height=new_height)
 
 def handle_mouse_input(stdscr, state: AppState) -> AppState: