feat(ui): add configurable message timestamps and card rendering layout

crates/owlen-tui/src/ui.rs

@@ -1029,14 +1029,15 @@ fn render_messages(frame: &mut Frame<'_>, area: Rect, app: &mut ChatApp) {
 
     // Calculate viewport dimensions for autoscroll calculations
     let viewport_height = area.height.saturating_sub(2) as usize; // subtract borders
-    let content_width = area.width.saturating_sub(4).max(20);
-    app.set_viewport_dimensions(viewport_height, usize::from(content_width));
+    let card_width = usize::from(area.width.saturating_sub(4).max(20));
+    let body_width = card_width.saturating_sub(4).max(12);
+    app.set_viewport_dimensions(viewport_height, body_width);
 
     let total_messages = app.message_count();
     let mut formatter = app.formatter().clone();
 
     // Reserve space for borders and the message indent so text fits within the block
-    formatter.set_wrap_width(usize::from(content_width));
+    formatter.set_wrap_width(body_width);
 
     // Build the lines for messages using cached rendering
     let mut lines: Vec<Line<'static>> = Vec::new();
@@ -1055,8 +1056,8 @@ fn render_messages(frame: &mut Frame<'_>, area: Rect, app: &mut ChatApp) {
             MessageRenderContext::new(
                 &mut formatter,
                 role_label_mode,
-                content_width as usize,
-                message_index + 1 == total_messages,
+                body_width,
+                card_width,
                 is_streaming,
                 app.get_loading_indicator(),
                 &theme,
@@ -1064,9 +1065,6 @@ fn render_messages(frame: &mut Frame<'_>, area: Rect, app: &mut ChatApp) {
             ),
         );
         lines.extend(message_lines);
-        if message_index + 1 < total_messages {
-            lines.push(Line::from(String::new()));
-        }
     }
 
     // Add loading indicator ONLY if we're loading and there are no messages at all,