fix：修复提示词工坊公开接口验证逻辑

backend/app/api/prompt_workshop.py

@@ -36,6 +36,45 @@ def get_user_identifier(user_id: str) -> str:
     return f"{INSTANCE_ID}:{user_id}"
 
 
+def get_user_identifier_from_request(request: Request) -> str:
+    """
+    从请求中获取用户标识
+    - 服务端模式：优先从 Header 获取（来自其他实例的代理请求）
+    - 客户端模式：从本地用户获取
+    """
+    if is_workshop_server():
+        # 服务端模式：检查是否来自其他实例的代理请求
+        instance_id = request.headers.get("X-Instance-ID")
+        header_user_id = request.headers.get("X-User-ID")
+        if instance_id and header_user_id:
+            # 来自其他实例的请求，使用 Header 中的用户标识
+            return header_user_id
+    
+    # 本地用户
+    user_id = getattr(request.state, 'user_id', None)
+    if not user_id:
+        raise HTTPException(status_code=401, detail="未登录或用户ID缺失")
+    return get_user_identifier(user_id)
+
+
+def get_optional_user_identifier(request: Request) -> Optional[str]:
+    """
+    获取可选的用户标识（用于公开API，可以没有用户）
+    """
+    if is_workshop_server():
+        # 服务端模式：检查是否来自其他实例的代理请求
+        instance_id = request.headers.get("X-Instance-ID")
+        header_user_id = request.headers.get("X-User-ID")
+        if instance_id and header_user_id:
+            return header_user_id
+    
+    # 本地用户
+    user_id = getattr(request.state, 'user_id', None)
+    if user_id:
+        return get_user_identifier(user_id)
+    return None
+
+
 def _item_to_dict(item: PromptWorkshopItem, is_liked: bool = False) -> dict:
     """将模型转换为字典"""
     return {
@@ -120,9 +159,8 @@ async def get_items(
     limit: int = 20,
     db: AsyncSession = Depends(get_db)
 ):
-    """获取提示词列表"""
-    user_id = getattr(request.state, 'user_id', None)
-    user_identifier = get_user_identifier(user_id) if user_id else None
+    """获取提示词列表（公开接口，不需要登录）"""
+    user_identifier = get_optional_user_identifier(request)
     
     if is_workshop_server():
         # 服务端模式：直接查询本地数据库
@@ -317,8 +355,7 @@ async def toggle_like(
     db: AsyncSession = Depends(get_db)
 ):
     """点赞/取消点赞"""
-    user_id = get_current_user_id(request)
-    user_identifier = get_user_identifier(user_id)
+    user_identifier = get_user_identifier_from_request(request)
     
     if is_workshop_server():
         # 检查是否已点赞
@@ -393,13 +430,30 @@ async def submit_prompt(
     db: AsyncSession = Depends(get_db)
 ):
     """提交提示词"""
-    user_id = get_current_user_id(request)
-    user_identifier = get_user_identifier(user_id)
+    user_identifier = get_user_identifier_from_request(request)
     
     # 获取用户显示名称
-    from app.user_manager import user_manager
-    user = await user_manager.get_user(user_id)
-    submitter_name = user.display_name if user else "未知用户"
+    submitter_name = "未知用户"
+    if is_workshop_server():
+        # 服务端模式：检查是否来自代理请求
+        instance_id = request.headers.get("X-Instance-ID")
+        if instance_id:
+            # 代理请求，从请求数据中获取提交者名称
+            submitter_name = data.author_display_name or "未知用户"
+        else:
+            # 本地请求
+            user_id = getattr(request.state, 'user_id', None)
+            if user_id:
+                from app.user_manager import user_manager
+                user = await user_manager.get_user(user_id)
+                submitter_name = user.display_name if user else "未知用户"
+    else:
+        # 客户端模式：本地用户
+        user_id = getattr(request.state, 'user_id', None)
+        if user_id:
+            from app.user_manager import user_manager
+            user = await user_manager.get_user(user_id)
+            submitter_name = user.display_name if user else "未知用户"
     
     if is_workshop_server():
         # 直接创建提交记录
@@ -448,8 +502,7 @@ async def get_my_submissions(
     db: AsyncSession = Depends(get_db)
 ):
     """获取我的提交记录"""
-    user_id = get_current_user_id(request)
-    user_identifier = get_user_identifier(user_id)
+    user_identifier = get_user_identifier_from_request(request)
     
     if is_workshop_server():
         query = select(PromptSubmission).where(
@@ -483,8 +536,7 @@ async def withdraw_submission(
     db: AsyncSession = Depends(get_db)
 ):
     """撤回待审核的提交"""
-    user_id = get_current_user_id(request)
-    user_identifier = get_user_identifier(user_id)
+    user_identifier = get_user_identifier_from_request(request)
     
     if is_workshop_server():
         result = await db.execute(