fix: restore static type hints for FixtureRegistry, load_fixtures, load_fixtures_by_context lost in lazy-import refactor (#347)

src/fastapi_toolsets/fixtures/__init__.py

@@ -1,7 +1,13 @@
 """Fixture system for seeding databases with dependency resolution."""
 
+from typing import TYPE_CHECKING
+
 from .enum import Context, LoadStrategy
 
+if TYPE_CHECKING:
+    from .registry import FixtureRegistry
+    from .utils import load_fixtures, load_fixtures_by_context
+
 __all__ = [
     "Context",
     "FixtureRegistry",