Feat: demo songs

src/views/options_view.rs

@@ -249,6 +249,12 @@ pub fn render(frame: &mut Frame, app: &App, link: &LinkState, area: Rect) {
                 focus == OptionsFocus::ResetOnboarding,
                 &theme,
             ),
+            render_option_line(
+                "Demo on startup",
+                if app.ui.load_demo_on_startup { "On" } else { "Off" },
+                focus == OptionsFocus::LoadDemoOnStartup,
+                &theme,
+            ),
         ]);
     }
 
@@ -358,6 +364,7 @@ fn option_description(focus: OptionsFocus) -> Option<&'static str> {
         OptionsFocus::MidiInput2 => Some("MIDI input device for channel group 3"),
         OptionsFocus::MidiInput3 => Some("MIDI input device for channel group 4"),
         OptionsFocus::ResetOnboarding => Some("Re-enable all dismissed guide popups"),
+        OptionsFocus::LoadDemoOnStartup => Some("Load a rotating demo song on fresh startup"),
     }
 }
 

src/views/patterns_view.rs

@@ -559,6 +559,9 @@ fn render_mini_tile_grid(
     let row_gap: u16 = 1;
     let max_tile_height: u16 = 4;
 
+    let max_rows = (area.height as usize + row_gap as usize) / (1 + row_gap as usize);
+    let num_rows = num_rows.min(max_rows.max(1));
+
     let available_for_rows =
         area.height.saturating_sub((num_rows.saturating_sub(1) as u16) * row_gap);
     let tile_height = (available_for_rows / num_rows as u16).min(max_tile_height).max(1);