fix: Python 3.12 compatibility (lazy annotations + TypeVar defaults)

Python 3.12 (CI's embedded interpreter) evaluates type annotations
eagerly, unlike 3.13+'s PEP 649 lazy defaults. Add `from __future__
import annotations` across videocode/ so self-referential and
TYPE_CHECKING-only annotations don't raise NameError at import time.

Also replace PEP 696 TypeVar(default=...) usages with
typing_extensions.TypeVar (3 sites), and rewrite position.py's combined
PEP 695+696 generic syntax (3.13+ only) to old-style Generic[T1, T2].

Author: anpawo

requirements.txt

@@ -3,4 +3,5 @@ shapely
 freetype-py
 uharfbuzz
 Pillow
-svgelements
+svgelements
+typing_extensions

videocode/__init__.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 #
 # VideoCode

videocode/color.py

@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
+
 #
 # Colors & gradients
 #

videocode/constants.py

@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
+
 #
 # Constant
 #

videocode/context.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 from abc import abstractmethod
 from typing import TYPE_CHECKING, Any, Callable

videocode/input/_inputs.py

@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
+
 #
 # All Inputs Types
 #

videocode/input/interface/Group.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 from copy import copy as _shallow_copy
-from typing import Any, TypeVar
+from typing import Any
+from typing_extensions import TypeVar
 from videocode.input.input import *
 from videocode.input.interface.Interface import Interface
 from videocode.template.effect.moveTo import groupMoveBy, groupMoveTo

videocode/input/interface/Interface.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 from abc import abstractmethod
 from typing import Any, Callable, Self

videocode/input/interface/Offset.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 import math
 

videocode/input/interface/StatefulGroup.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 
+from __future__ import annotations
 
 from copy import copy as _shallow_copy
-from typing import Callable, TypeVar
+from typing import Callable
+from typing_extensions import TypeVar
 from videocode.input.input import *
 from videocode.input.interface.Group import Group
 from videocode.shader.vertexShader.translate import translate