feat(ai-avatar): 渲染完成后自动保存成片记录到成片库

- 在 execute_render 方法的 job.status=completed 之后，自动创建 GeneratedVideo 记录
- 复用现有 GeneratedVideo 模型和 SQLAlchemyGeneratedVideoRepository
- 成片记录包含：视频URL、封面URL、时长、用户ID、项目ID
- 生成参数中记录来源(render_job_id)以便追溯
- 创建失败时仅打 warning 日志，不影响渲染任务状态

apps/api/app/services/ai_avatar_render_service.py

@@ -322,6 +322,37 @@ class AiAvatarRenderService:
             self.db.commit()
             logger.info("渲染任务完成: %s", job_id)
 
+            # 7. 自动保存成片记录到成片库
+            if job.output_video_url:
+                try:
+                    from packages.domain.generated_video import GeneratedVideo
+                    from packages.adapters.sqlalchemy_impl.generated_video_repository import (
+                        SQLAlchemyGeneratedVideoRepository,
+                    )
+
+                    clip_name = f"AI数字人_{job_id[:8]}"
+                    clip = GeneratedVideo.create(
+                        project_id=job.project_id,
+                        generation_task_id=job.lipsync_job_id,
+                        name=clip_name,
+                        file_url=job.output_video_url,
+                        user_id=job.user_id,
+                        duration=job.output_duration or 0.0,
+                        thumbnail_url=job.output_cover_url or None,
+                        generation_params={
+                            "source": "ai_avatar_render",
+                            "render_job_id": job.id,
+                        },
+                    )
+                    video_repo = SQLAlchemyGeneratedVideoRepository(self.db)
+                    video_repo.create(clip)
+                    logger.info("成片记录已保存到成片库: clip_id=%s, render_job=%s", clip.id, job_id)
+                except Exception as clip_err:
+                    logger.warning(
+                        "自动保存成片记录失败（不影响渲染任务状态）: render_job=%s, error=%s",
+                        job_id, clip_err,
+                    )
+
         except AiAvatarRenderError as exc:
             job.status = "failed"
             job.error_message = str(exc)
@@ -376,7 +407,7 @@ class AiAvatarRenderService:
         else:
             filter_arg = ""
 
-        return f"ffmpeg {inputs} {filter_arg} -c:v libx264 -preset fast -crf 23 -y {output_path}"
+        return f"ffmpeg {inputs} {filter_arg} -c:v libx264 -preset veryfast -crf 23 -y {output_path}"
 
     def _upload_to_oss(self, local_path: str, oss_key: str) -> str:
         """上传文件到 OSS，返回 URL.