checkpoint: SQLite 清理——业务/测试层统一 PostgreSQL（删 aiosqlite/fakeredis）

- setting: DATABASE_TYPE 收窄为 postgres，DB_URI/ASYNC_DB_URI 去 sqlite 分支
- database: create_async_engine_and_session 去 sqlite 分支（同步 psycopg 引擎保留给 jobstore）
- number_gen: 去 DATABASE_TYPE 非 postgres 早退（advisory lock 恒定走 PG）
- chat/crud: 删 SqliteDb 分支（agno 无硬依赖）
- pyproject/requirements/uv.lock: 删 aiosqlite、fakeredis；conftest 口径注释同步
- test_stat_analysis_tc: docstring 口径 SQLite→PG

backend/app/core/database.py

@@ -49,29 +49,19 @@ def create_async_engine_and_session(db_url: str = settings.ASYNC_DB_URI) -> tupl
     - tuple[AsyncEngine, async_sessionmaker[AsyncSession]]: 异步数据库引擎和会话工厂。
     """
     try:
-        # 异步数据库引擎
-        if settings.DATABASE_TYPE == "sqlite":
-            async_engine = create_async_engine(
-                url=db_url,
-                echo=settings.DATABASE_ECHO,
-                echo_pool=settings.ECHO_POOL,
-                pool_pre_ping=settings.POOL_PRE_PING,
-                future=settings.FUTURE,
-                pool_recycle=settings.POOL_RECYCLE,
-            )
-        else:
-            async_engine = create_async_engine(
-                url=db_url,
-                echo=settings.DATABASE_ECHO,
-                echo_pool=settings.ECHO_POOL,
-                pool_pre_ping=settings.POOL_PRE_PING,
-                future=settings.FUTURE,
-                pool_recycle=settings.POOL_RECYCLE,
-                pool_size=settings.POOL_SIZE,
-                max_overflow=settings.MAX_OVERFLOW,
-                pool_timeout=settings.POOL_TIMEOUT,
-                pool_use_lifo=settings.POOL_USE_LIFO,
-            )
+        # 异步数据库引擎（统一 PostgreSQL 连接池参数）
+        async_engine = create_async_engine(
+            url=db_url,
+            echo=settings.DATABASE_ECHO,
+            echo_pool=settings.ECHO_POOL,
+            pool_pre_ping=settings.POOL_PRE_PING,
+            future=settings.FUTURE,
+            pool_recycle=settings.POOL_RECYCLE,
+            pool_size=settings.POOL_SIZE,
+            max_overflow=settings.MAX_OVERFLOW,
+            pool_timeout=settings.POOL_TIMEOUT,
+            pool_use_lifo=settings.POOL_USE_LIFO,
+        )
     except Exception as e:
         logger.error(f"❌ 数据库连接失败 {e}")
         raise