fix(ui): 调整卡牌预制体尺寸并修复开始按钮状态逻辑

- 修正卡牌预制体的局部位置、尺寸模式和内容大小，优化显示效果
- 隐藏预制体中不必要的节点以提升性能
- 重构开始按钮状态控制逻辑，改为根据游戏阶段动态更新按钮的可点击状态
- 移除直接隐藏按钮的代码，确保按钮在准备阶段且未暂停时可点击

assets/resources/gui/element/card.prefab

@@ -863,7 +863,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": 0.5,
+      "y": 0,
       "z": 0
     },
     "_lrot": {
@@ -995,7 +995,7 @@
     },
     "_type": 0,
     "_fillType": 0,
-    "_sizeMode": 1,
+    "_sizeMode": 0,
     "_fillCenter": {
       "__type__": "cc.Vec2",
       "x": 0,
@@ -1042,8 +1042,8 @@
     },
     "_contentSize": {
       "__type__": "cc.Size",
-      "width": 164,
-      "height": 223
+      "width": 156,
+      "height": 210
     },
     "_anchorPoint": {
       "__type__": "cc.Vec2",
@@ -3243,7 +3243,7 @@
         "__id__": 181
       }
     ],
-    "_active": true,
+    "_active": false,
     "_components": [
       {
         "__id__": 189
@@ -8440,7 +8440,7 @@
         "__id__": 390
       }
     ],
-    "_active": true,
+    "_active": false,
     "_components": [
       {
         "__id__": 396