refactor(hero&mission): 调整英雄站位逻辑与配置

1.  修改游戏地平线Y轴偏移至100，适配新的UI布局
2.  为英雄属性组件添加分路与排位字段并初始化
3.  重构英雄站位分配逻辑，使用新增字段记录英雄位置
4.  更新地图与UI预制体的布局偏移适配新的游戏地平线

assets/resources/game/map/map_rpg.prefab

@@ -587,7 +587,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": 107.444,
+      "y": 237.503,
       "z": 0
     },
     "_lrot": {
@@ -723,7 +723,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": 336.936,
+      "y": 428.991,
       "z": 0
     },
     "_lrot": {
@@ -862,7 +862,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": 102.513,
+      "y": 193.723,
       "z": 0
     },
     "_lrot": {
@@ -978,7 +978,7 @@
     "_left": 0,
     "_right": 0,
     "_top": 0,
-    "_bottom": 152.513,
+    "_bottom": 243.723,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
     "_isAbsLeft": true,
@@ -1037,7 +1037,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": 102.513,
+      "y": 193.723,
       "z": 0
     },
     "_lrot": {
@@ -1153,7 +1153,7 @@
     "_left": 0,
     "_right": 0,
     "_top": 0,
-    "_bottom": 152.513,
+    "_bottom": 243.723,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
     "_isAbsLeft": true,
@@ -1317,6 +1317,8 @@
       "__id__": 0
     },
     "fileId": "e7P5mh6mhLga+0q7X7vlTP",
+    "instance": null,
+    "targetOverrides": null,
     "nestedPrefabInstanceRoots": null
   },
   {
@@ -1346,7 +1348,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": -233.935,
+      "y": -120,
       "z": 0
     },
     "_lrot": {
@@ -1462,7 +1464,7 @@
     "_left": 0,
     "_right": 0,
     "_top": 0,
-    "_bottom": -183.935,
+    "_bottom": -70,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
     "_isAbsLeft": true,
@@ -1490,6 +1492,8 @@
       "__id__": 0
     },
     "fileId": "6bE0ieRMBGyYHdxvuJ03FA",
+    "instance": null,
+    "targetOverrides": null,
     "nestedPrefabInstanceRoots": null
   },
   {