Initial commit: AI Video Assistant fullstack platform.

Add pipecat-based backend with WebRTC/WS voice routes, Next.js frontend, and Docker Compose orchestration.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/db/session.py

@@ -0,0 +1,29 @@
+"""异步数据库引擎 + 会话。
+
+- engine / SessionLocal:全局单例
+- get_session:FastAPI 依赖,按请求注入一个会话
+- init_db:启动时建表(MVP 用 create_all;表结构稳定后切 alembic 迁移,对齐 dograh)
+"""
+
+from collections.abc import AsyncGenerator
+
+import config
+from db.models import Base
+from sqlalchemy.ext.asyncio import (
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+
+engine = create_async_engine(config.DATABASE_URL, echo=False, pool_pre_ping=True)
+SessionLocal = async_sessionmaker(engine, expire_on_commit=False)
+
+
+async def get_session() -> AsyncGenerator[AsyncSession, None]:
+    async with SessionLocal() as session:
+        yield session
+
+
+async def init_db() -> None:
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)