feat: Add various seeds that grow on dirt, including grass blades, flowers, and trees

index.html

@@ -16,6 +16,8 @@
                 <button id="stone-btn">Stone</button>
                 <button id="grass-btn">Grass</button>
                 <button id="wood-btn">Wood</button>
+                <button id="seed-btn">Seed</button>
+                <button id="tree-seed-btn">Tree Seed</button>
                 <button id="eraser-btn">Eraser</button>
             </div>
             <div class="navigation">