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_tts_cos_keys.py

@@ -0,0 +1,39 @@
+"""COS key collection for conversation TTS URLs."""
+
+from app.core.cos_url_keys import (
+    collect_cos_keys_from_conversation_history,
+    collect_cos_keys_from_tts_url_list,
+)
+
+
+def test_collect_from_history_empty():
+    assert collect_cos_keys_from_conversation_history([]) == set()
+
+
+def test_collect_from_history_ai_tts_urls(monkeypatch):
+    monkeypatch.setattr(
+        "app.core.cos_url_keys.settings.tencent_cos_bucket",
+        "bucket",
+        raising=False,
+    )
+    monkeypatch.setattr(
+        "app.core.cos_url_keys.settings.tencent_cos_region",
+        "ap-guangzhou",
+        raising=False,
+    )
+    url = "https://bucket.cos.ap-guangzhou.myqcloud.com/conversations/c1/tts/a.mp3"
+    hist = [
+        {"role": "human", "content": "hi", "messageType": "text"},
+        {
+            "role": "ai",
+            "content": "hello",
+            "messageType": "text",
+            "ttsAudioUrls": [url],
+        },
+    ]
+    keys = collect_cos_keys_from_conversation_history(hist)
+    assert keys == {"conversations/c1/tts/a.mp3"}
+
+
+def test_collect_from_tts_url_list_none():
+    assert collect_cos_keys_from_tts_url_list(None) == set()