fix: allow dry_run mode without API key for prompt preview

app/services/plan_generator.py

@@ -205,9 +205,6 @@ def generate_ai_report(
     if not prompt_template:
         prompt_template = config.get("prompt_template", "")
 
-    if not api_key:
-        return None, None, "未配置API Key，请在设置页面配置", None
-
     # 从问题文件内容中提取关键信息
     def extract_problem_info(content_str):
         if not content_str or not isinstance(content_str, str):
@@ -310,6 +307,10 @@ def generate_ai_report(
             "student_goals_length": len(student_goals_text),
         }
 
+    # API调用需要 Key
+    if not api_key:
+        return None, None, "未配置API Key，请在设置页面配置", None
+
     # 调用API
     headers = {
         "Authorization": f"Bearer {api_key}",