fix: resolve lifetime annotation warnings

- Add explicit lifetime annotations to function return types
- Fix ascii_digits.rs: Vec<Line> to Vec<Line<'_>>
- Fix mario_animation.rs: Canvas<impl Fn> to Canvas<'_, impl Fn>

Resolves mismatched_lifetime_syntaxes warnings for cleaner compilation

Author: punk2049

src/ascii_digits.rs

@@ -90,7 +90,7 @@ pub fn get_digit_lines(digit: char) -> Vec<&'static str> {
     }
 }
 
-pub fn create_time_display_lines(time_str: &str, color: Color) -> Vec<Line> {
+pub fn create_time_display_lines(time_str: &str, color: Color) -> Vec<Line<'_>> {
     let chars: Vec<char> = time_str.chars().collect();
     let mut lines = vec![String::new(); 5]; // 5 lines for each digit
 

src/mario_animation.rs

@@ -273,7 +273,7 @@ impl MarioAnimation {
         self.mushroom_particles.retain(|p| p.life > 0.0);
     }
 
-    pub fn render(&self, _area: Rect) -> Canvas<impl Fn(&mut Context)> {
+    pub fn render(&self, _area: Rect) -> Canvas<'_, impl Fn(&mut Context)> {
         Canvas::default()
             .marker(Marker::Braille)
             .x_bounds([0.0, 240.0])