fix(api): 剪辑计划详情/列表接口rendered_url签名转换，修复OSS 403

#454 OSS 403收尾：
- generation status接口的video_url签名已在#467修复
- 本次修复plan详情/列表接口直接返回config的问题
- _to_response中对config.rendered_url自动做签名转换
- 覆盖GET /{plan_id}、列表、创建、更新、复制等所有返回EditPlanResponse的接口
- 新增3个单元测试，47个测试全过
- 失败降级：签名异常时返回原始URL，不阻塞主流程

apps/api/app/api/routes/edit_plans.py

@@ -22,6 +22,7 @@ from datetime import datetime
 from typing import Any, List, Optional
 
 from app.auth import AuthenticatedUser, get_current_user
+from app.core.storage import get_storage_service
 from app.dependencies import (
     get_asset_library_repository,
     get_asset_repository,
@@ -251,6 +252,16 @@ class GenerateFromTemplateResponse(BaseModel):
 
 
 def _to_response(p: EditPlan) -> EditPlanResponse:
+    # 对 config 中的 rendered_url 做签名转换（私有bucket裸URL会403）
+    config = dict(p.config) if p.config else {}
+    raw_rendered_url = config.get("rendered_url", "")
+    if raw_rendered_url:
+        try:
+            storage = get_storage_service()
+            config["rendered_url"] = storage.get_download_url(raw_rendered_url, expires_seconds=86400)
+        except Exception as e:
+            logger.warning("剪辑计划rendered_url签名失败，返回原始URL: plan_id=%s error=%s", p.id, e)
+
     return EditPlanResponse(
         id=p.id,
         template_id=p.template_id,
@@ -260,7 +271,7 @@ def _to_response(p: EditPlan) -> EditPlanResponse:
         result_count=getattr(p, "result_count", 0),
         project_id=p.project_id or "",
         created_by_user_id=p.created_by_user_id or "",
-        config=p.config,
+        config=config,
         created_at=p.created_at,
         updated_at=p.updated_at,
     )