feat(ui): shrink system/status output height and improve file panel toggle feedback

- Adjust layout constraint from 5 to 4 lines to match 2 lines of content plus borders.
- Refactor file focus key handling to toggle the file panel state and set status messages (“Files panel shown” / “Files panel hidden”) instead of always expanding and using a static status.

crates/owlen-tui/src/chat_app.rs

@@ -3938,9 +3938,15 @@ impl ChatApp {
                     && matches!(key.code, KeyCode::Char('p') | KeyCode::Char('P'));
 
                 if is_file_focus_key && matches!(self.mode, InputMode::Normal) {
-                    self.expand_file_panel();
-                    self.focused_panel = FocusedPanel::Files;
-                    self.status = "Files panel focused".to_string();
+                    let was_collapsed = self.is_file_panel_collapsed();
+                    self.toggle_file_panel();
+                    if was_collapsed && !self.is_file_panel_collapsed() {
+                        self.status = "Files panel shown".to_string();
+                    } else if !was_collapsed && self.is_file_panel_collapsed() {
+                        self.status = "Files panel hidden".to_string();
+                    } else {
+                        // No visual change (e.g., width constraints), keep prior status
+                    }
                     return Ok(AppState::Running);
                 }
 

crates/owlen-tui/src/ui.rs

@@ -283,7 +283,7 @@ pub fn render_chat(frame: &mut Frame<'_>, app: &mut ChatApp) {
     }
 
     constraints.push(Constraint::Length(input_height)); // Input
-    constraints.push(Constraint::Length(5)); // System/Status output (3 lines content + 2 borders)
+    constraints.push(Constraint::Length(4)); // System/Status output (2 lines content + 2 borders)
     constraints.push(Constraint::Length(3)); // Mode and shortcuts bar
 
     let layout = Layout::default()