Drop redundant from __future__ import annotations

Python 3.13 (the package floor) evaluates the runtime PEP 604 / PEP 695
syntax natively. Drop the directive for file-level idiom consistency
with the rest of the codebase.

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

Author: antoineleclair

src/dqlitedbapi/_constants.py

@@ -23,8 +23,6 @@
 this constant is ahead of what the server reports.
 """
 
-from __future__ import annotations
-
 from typing import Final
 
 SQLITE_VERSION_INFO: Final[tuple[int, int, int]] = (3, 35, 0)