feat: enhance debug visuals with cursor-based effect

tests/debug_rendering.rs

@@ -0,0 +1,34 @@
+use glam::Vec2;
+use pacman::entity::graph::{Graph, Node};
+use pacman::map::render::MapRenderer;
+
+#[test]
+fn test_find_nearest_node() {
+    let mut graph = Graph::new();
+
+    // Add some test nodes
+    let node1 = graph.add_node(Node {
+        position: Vec2::new(10.0, 10.0),
+    });
+    let node2 = graph.add_node(Node {
+        position: Vec2::new(50.0, 50.0),
+    });
+    let node3 = graph.add_node(Node {
+        position: Vec2::new(100.0, 100.0),
+    });
+
+    // Test cursor near node1
+    let cursor_pos = Vec2::new(12.0, 8.0);
+    let nearest = MapRenderer::find_nearest_node(&graph, cursor_pos);
+    assert_eq!(nearest, Some(node1));
+
+    // Test cursor near node2
+    let cursor_pos = Vec2::new(45.0, 55.0);
+    let nearest = MapRenderer::find_nearest_node(&graph, cursor_pos);
+    assert_eq!(nearest, Some(node2));
+
+    // Test cursor near node3
+    let cursor_pos = Vec2::new(98.0, 102.0);
+    let nearest = MapRenderer::find_nearest_node(&graph, cursor_pos);
+    assert_eq!(nearest, Some(node3));
+}