修复：CI 部署环境与 ref 错配、迁移碎片化、图片意图 source_span、章节物化脏版式、会话历史与本地语音不一致

新增：TTS 上传 COS 与分片、章节 reading_segments 物化与快照、markdown 清洗、会话消息 repository、语音 store 重构与相关测试

api/app/features/story/service.py

@@ -61,7 +61,6 @@ async def _extract_and_store_image_intent(
             return
         existing.caption = result.caption
         existing.prompt_brief = result.prompt_brief
-        existing.source_span = result.source_span
         existing.style_profile = result.style_profile
         existing.status = "pending"
         existing.error = None
@@ -74,7 +73,6 @@ async def _extract_and_store_image_intent(
         existing.story_version_id = version.id
         existing.caption = result.caption
         existing.prompt_brief = result.prompt_brief
-        existing.source_span = result.source_span
         existing.style_profile = result.style_profile
         existing.status = "pending"
         existing.error = None
@@ -88,7 +86,6 @@ async def _extract_and_store_image_intent(
         story_version_id=version.id,
         caption=result.caption,
         prompt_brief=result.prompt_brief,
-        source_span=result.source_span,
         style_profile=result.style_profile,
     )