Use PEP 673 Self for DqliteConnection / ConnectionPool __aenter__ returns

See dbapi sibling commit for full rationale: subclass-correct
context-manager / chainable-return signatures.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqliteclient/connection.py

@@ -11,7 +11,7 @@
 from collections.abc import AsyncIterator, Awaitable, Callable, Mapping, Sequence
 from contextlib import asynccontextmanager
 from types import TracebackType
-from typing import Any, Final, NoReturn
+from typing import Any, Final, NoReturn, Self
 
 from dqliteclient.exceptions import (
     DataError,
@@ -1325,7 +1325,7 @@ async def _abort_protocol(self) -> None:
                 exc_info=True,
             )
 
-    async def __aenter__(self) -> "DqliteConnection":
+    async def __aenter__(self) -> Self:
         await self.connect()
         return self
 

src/dqliteclient/pool.py

@@ -7,7 +7,7 @@
 from collections.abc import AsyncIterator, Sequence
 from contextlib import asynccontextmanager
 from types import TracebackType
-from typing import Any, Final, NoReturn
+from typing import Any, Final, NoReturn, Self
 
 from dqliteclient import connection as _conn_mod
 from dqliteclient.cluster import ClusterClient
@@ -1503,7 +1503,7 @@ async def close(self) -> None:
         # returning to the pool. Force-closing them here would race with
         # the acquire context manager and corrupt _size.
 
-    async def __aenter__(self) -> "ConnectionPool":
+    async def __aenter__(self) -> Self:
         await self.initialize()
         return self