feat: Implement Aliyun TTS backend integration and API key management

qwen3-tts-backend/requirements.txt

@@ -6,6 +6,7 @@ python-multipart==0.0.12
 python-jose[cryptography]==3.3.0
 passlib==1.7.4
 bcrypt==3.2.2
+cryptography>=41.0.0
 sqlalchemy==2.0.35
 aiosqlite==0.20.0
 soundfile==0.12.1
@@ -17,3 +18,4 @@ pytest==8.3.0
 pytest-cov==4.1.0
 pytest-asyncio==0.23.0
 httpx==0.27.0
+websockets>=12.0