feat: Implement climbing system and tree collision avoidance for player

This commit adds:
1. Player climbing mechanism for small steps
2. Collision avoidance with trees (WOOD and LEAF pixels)
3. Enhanced animation states for climbing and jumping
4. Improved player movement and collision detection

js/entities/entity.js

@@ -149,6 +149,20 @@ class Entity {
     isPixelSolid(x, y) {
         // Use ceiling for y coordinate to better detect ground below
         const pixel = getPixel(Math.floor(x), Math.ceil(y));
+        
+        // For player entity, don't collide with trees (WOOD and LEAF)
+        if (this.type === ENTITY_TYPES.PLAYER) {
+            return pixel !== EMPTY && 
+                   pixel !== WATER && 
+                   pixel !== FIRE &&
+                   pixel !== SQUARE && 
+                   pixel !== CIRCLE && 
+                   pixel !== TRIANGLE &&
+                   pixel !== WOOD &&
+                   pixel !== LEAF;
+        }
+        
+        // For other entities, use the original collision detection
         return pixel !== EMPTY && 
                pixel !== WATER && 
                pixel !== FIRE &&