feat: 成长路径页面增加岗位全选按钮，调整下方区域高度

frontend/src/views/manager/growth-path-management.vue

@@ -150,6 +150,7 @@
                   <el-input v-model="editingPath.name" placeholder="请输入路径名称" />
                 </el-form-item>
                 <el-form-item label="关联岗位" class="form-item-half">
+                  <div class="position-select-wrapper">
                     <el-select 
                       v-model="editingPath.position_ids" 
                       placeholder="选择关联岗位" 
@@ -166,6 +167,16 @@
                         :value="pos.id" 
                       />
                     </el-select>
+                    <el-button 
+                      link 
+                      type="primary" 
+                      size="small" 
+                      @click="handleSelectAllPositions"
+                      class="select-all-btn"
+                    >
+                      {{ isAllPositionsSelected ? '取消全选' : '全选' }}
+                    </el-button>
+                  </div>
                 </el-form-item>
               </div>
               <div class="form-row">
@@ -529,6 +540,11 @@ const totalDuration = computed(() => {
   }, 0)
 })
 
+const isAllPositionsSelected = computed(() => {
+  if (!editingPath.value?.position_ids || positions.value.length === 0) return false
+  return editingPath.value.position_ids.length === positions.value.length
+})
+
 // ========== 方法 ==========
 
 /**
@@ -820,6 +836,20 @@ const getStageNodes = (stageName: string) => {
   return editingPath.value?.nodes?.filter(n => n.stage_name === stageName) || []
 }
 
+/**
+ * 全选/取消全选岗位
+ */
+const handleSelectAllPositions = () => {
+  if (!editingPath.value) return
+  const allIds = positions.value.map(p => p.id)
+  // 如果当前已全选，则取消全选
+  if (editingPath.value.position_ids?.length === allIds.length) {
+    editingPath.value.position_ids = []
+  } else {
+    editingPath.value.position_ids = [...allIds]
+  }
+}
+
 /**
  * 添加课程
  */
@@ -1056,6 +1086,21 @@ onMounted(() => {
         :deep(.el-form-item) {
           margin-bottom: 0;
         }
+
+        .position-select-wrapper {
+          display: flex;
+          align-items: center;
+          gap: 8px;
+
+          .el-select {
+            flex: 1;
+          }
+
+          .select-all-btn {
+            white-space: nowrap;
+            flex-shrink: 0;
+          }
+        }
       }
 
       .stages-section {
@@ -1131,10 +1176,10 @@ onMounted(() => {
 
     // 下方区域
     .editor-bottom {
-      flex: 1;
+      flex: 2;
       display: flex;
       gap: 16px;
-      min-height: 0;
+      min-height: 400px;
 
       // 左侧课程库 1/3
       .course-library-panel {