Declare __all__ on the Connection modules to match the cursor modules

Both cursor modules declare their public surface via __all__ (just
"Cursor" / "AsyncCursor"), but the connection modules did not. Export
Connection and AsyncConnection symmetrically so submodule-level imports
and tooling agree on the intended public API.

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

Author: antoineleclair

src/dqlitedbapi/aio/connection.py

@@ -12,6 +12,8 @@
 from dqlitedbapi.connection import _is_no_transaction_error
 from dqlitedbapi.exceptions import InterfaceError, OperationalError, ProgrammingError
 
+__all__ = ["AsyncConnection"]
+
 
 class AsyncConnection:
     """Async database connection."""

src/dqlitedbapi/connection.py

@@ -14,6 +14,8 @@
 from dqlitedbapi.cursor import Cursor
 from dqlitedbapi.exceptions import InterfaceError, OperationalError, ProgrammingError
 
+__all__ = ["Connection"]
+
 # SQLite result codes for "you tried to COMMIT/ROLLBACK but there's no
 # transaction active." SQLite returns ``SQLITE_ERROR`` (1) most of the
 # time; some code paths return ``SQLITE_MISUSE`` (21). Check the