feat: Add new materials (dirt, stone, grass, wood) with unique behaviors

index.html

@@ -12,6 +12,10 @@
             <div class="tools">
                 <button id="sand-btn" class="active">Sand</button>
                 <button id="water-btn">Water</button>
+                <button id="dirt-btn">Dirt</button>
+                <button id="stone-btn">Stone</button>
+                <button id="grass-btn">Grass</button>
+                <button id="wood-btn">Wood</button>
                 <button id="eraser-btn">Eraser</button>
             </div>
             <div class="navigation">