feat: 成长路径支持多岗位关联 + 增强拖拽功能

前端:
- 岗位选择改为多选模式
- 增强拖拽视觉反馈（高亮、动画提示）
- 列表显示多个岗位标签

后端:
- 添加 position_ids 字段支持多岗位
- 兼容旧版 position_id 单选数据
- 返回 position_names 数组

backend/app/services/growth_path_service.py

@@ -58,12 +58,21 @@ class GrowthPathService:
         if existing.scalar_one_or_none():
             raise ValueError(f"成长路径名称 '{data.name}' 已存在")
 
+        # 处理岗位关联：优先使用 position_ids，兼容 position_id
+        position_ids = data.position_ids
+        position_id = data.position_id
+        if position_ids is None and position_id is not None:
+            position_ids = [position_id]
+        elif position_ids and not position_id:
+            position_id = position_ids[0] if position_ids else None
+
         # 创建成长路径
         growth_path = GrowthPath(
             name=data.name,
             description=data.description,
             target_role=data.target_role,
-            position_id=data.position_id,
+            position_id=position_id,
+            position_ids=position_ids,
             stages=[s.model_dump() for s in data.stages] if data.stages else None,
             estimated_duration_days=data.estimated_duration_days,
             is_active=data.is_active,
@@ -110,6 +119,12 @@ class GrowthPathService:
         if 'stages' in update_data and update_data['stages']:
             update_data['stages'] = [s.model_dump() if hasattr(s, 'model_dump') else s for s in update_data['stages']]
         
+        # 处理 position_ids 和 position_id 的兼容
+        if 'position_ids' in update_data and update_data['position_ids']:
+            update_data['position_id'] = update_data['position_ids'][0]
+        elif 'position_id' in update_data and update_data['position_id'] and 'position_ids' not in update_data:
+            update_data['position_ids'] = [update_data['position_id']]
+        
         for key, value in update_data.items():
             setattr(growth_path, key, value)
 
@@ -173,12 +188,20 @@ class GrowthPathService:
         if not growth_path:
             return None
 
-        # 获取岗位名称
-        position_name = None
-        if growth_path.position_id:
-            position = await db.get(Position, growth_path.position_id)
+        # 获取岗位名称（支持多岗位）
+        position_ids = growth_path.position_ids or []
+        # 兼容旧数据
+        if not position_ids and growth_path.position_id:
+            position_ids = [growth_path.position_id]
+        
+        position_names = []
+        for pid in position_ids:
+            position = await db.get(Position, pid)
             if position:
-                position_name = position.name
+                position_names.append(position.name)
+        
+        # 兼容旧版 position_name（取第一个）
+        position_name = position_names[0] if position_names else None
 
         # 获取课程名称
         nodes_data = []
@@ -208,7 +231,9 @@ class GrowthPathService:
             "description": growth_path.description,
             "target_role": growth_path.target_role,
             "position_id": growth_path.position_id,
+            "position_ids": position_ids,
             "position_name": position_name,
+            "position_names": position_names,
             "stages": growth_path.stages,
             "estimated_duration_days": growth_path.estimated_duration_days,
             "is_active": growth_path.is_active,
@@ -250,12 +275,18 @@ class GrowthPathService:
 
         items = []
         for path in paths:
-            # 获取岗位名称
-            position_name = None
-            if path.position_id:
-                position = await db.get(Position, path.position_id)
+            # 获取岗位名称（支持多岗位）
+            position_ids = path.position_ids or []
+            if not position_ids and path.position_id:
+                position_ids = [path.position_id]
+            
+            position_names = []
+            for pid in position_ids:
+                position = await db.get(Position, pid)
                 if position:
-                    position_name = position.name
+                    position_names.append(position.name)
+            
+            position_name = position_names[0] if position_names else None
 
             # 获取节点数量
             node_count_result = await db.execute(
@@ -273,7 +304,9 @@ class GrowthPathService:
                 "name": path.name,
                 "description": path.description,
                 "position_id": path.position_id,
+                "position_ids": position_ids,
                 "position_name": position_name,
+                "position_names": position_names,
                 "is_active": path.is_active,
                 "node_count": node_count,
                 "estimated_duration_days": path.estimated_duration_days,