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/tests/test_chapter_markdown_compose.py

@@ -2,36 +2,43 @@ import unittest
 
 from app.features.memoir.chapter_markdown_compose import (
     compose_ordered_stories_to_markdown,
+    compose_ordered_stories_to_pdf_markdown,
     materialize_chapter_markdown_from_loaded_chapter,
 )
 
 
 class ChapterMarkdownComposeTest(unittest.TestCase):
-    def test_orders_and_separates_with_headings(self):
+    def test_joins_bodies_with_hr_only_no_story_headings(self):
         md = compose_ordered_stories_to_markdown(
             [("第一章", "正文A"), ("第二章", "正文B")]
         )
-        self.assertIn("## 第一章", md)
+        self.assertNotIn("##", md)
         self.assertIn("正文A", md)
-        self.assertIn("## 第二章", md)
         self.assertIn("正文B", md)
         self.assertIn("\n\n---\n\n", md)
         self.assertTrue(md.index("正文A") < md.index("---"))
-        self.assertTrue(md.index("---") < md.index("第二章"))
-        self.assertTrue(md.index("第一章") < md.index("第二章"))
+        self.assertTrue(md.index("---") < md.index("正文B"))
 
     def test_preserves_asset_refs(self):
         body = "![x](asset://abc-123)"
         md = compose_ordered_stories_to_markdown([("S", body)])
         self.assertIn("asset://abc-123", md)
 
-    def test_empty_title_uses_fallback(self):
+    def test_empty_title_still_composes_body(self):
         md = compose_ordered_stories_to_markdown([("", "仅正文")])
-        self.assertIn("## 故事", md)
+        self.assertEqual(md, "仅正文")
+        self.assertNotIn("##", md)
 
-    def test_empty_body_keeps_heading_only(self):
+    def test_empty_body_skipped(self):
         md = compose_ordered_stories_to_markdown([("仅标题", "")])
-        self.assertEqual(md, "## 仅标题")
+        self.assertEqual(md, "")
+
+    def test_pdf_markdown_includes_story_headings(self):
+        md = compose_ordered_stories_to_pdf_markdown(
+            [("第一章", "正文A"), ("第二章", "正文B")]
+        )
+        self.assertIn("## 第一章", md)
+        self.assertIn("## 第二章", md)
 
     def test_materialize_respects_order_index(self):
         class _S:
@@ -56,3 +63,4 @@ class ChapterMarkdownComposeTest(unittest.TestCase):
         )()
         md = materialize_chapter_markdown_from_loaded_chapter(ch)
         self.assertLess(md.index("先"), md.index("后"))
+        self.assertNotIn("##", md)