refactor(gui): 更新加载界面资源及配置

- 删除未使用的背景资源mp2.png及其相关文件
- 更新umps.plist和umps.png资源文件
- 调整loading.prefab的激活状态和位置
- 优化资源引用和配置

assets/resources/gui/umps.plist

@@ -4,6 +4,23 @@
     <dict>
         <key>frames</key>
         <dict>
+            <key>Background_01.png</key>
+            <dict>
+                <key>aliases</key>
+                <array/>
+                <key>anchor</key>
+                <string>{0.5,0.5}</string>
+                <key>spriteOffset</key>
+                <string>{0,0}</string>
+                <key>spriteSize</key>
+                <string>{324,666}</string>
+                <key>spriteSourceSize</key>
+                <string>{324,666}</string>
+                <key>textureRect</key>
+                <string>{{651,1},{324,666}}</string>
+                <key>textureRotated</key>
+                <false/>
+            </dict>
             <key>Bg.png</key>
             <dict>
                 <key>aliases</key>
@@ -33,9 +50,9 @@
             <key>realTextureFileName</key>
             <string>umps.png</string>
             <key>size</key>
-            <string>{650,662}</string>
+            <string>{976,668}</string>
             <key>smartupdate</key>
-            <string>$TexturePacker:SmartUpdate:50b059cd3a009dcc17c5bd06e4efd7e8:dd029976cf467eb4b1b3086e57e7c576:318abc3a8f3ad8d09018e87dff1f2449$</string>
+            <string>$TexturePacker:SmartUpdate:0262deb64e2f94e198de7eb4d600e44a:2f1bc9081585fe2f0d4e0317b671cd8c:318abc3a8f3ad8d09018e87dff1f2449$</string>
             <key>textureFileName</key>
             <string>umps.png</string>
         </dict>