src/vcspull/types.py(refactor[typing]): remove typing_extensions dependency

why: keep runtime installs free of typing_extensions while still supporting optional fields.
what:
- split ConfigDict into required/optional TypedDict mixins instead of relying on NotRequired.
- drop the typing_extensions import entirely.

Author: tony

src/vcspull/types.py

@@ -31,9 +31,7 @@
 
 import pathlib
 import typing as t
-from typing import TypeAlias
-
-from typing_extensions import NotRequired, TypedDict
+from typing import TypeAlias, TypedDict
 
 if t.TYPE_CHECKING:
     from libvcs._internal.types import StrPath, VCSLiteral
@@ -54,16 +52,25 @@ class RawConfigDict(t.TypedDict):
 RawConfig = dict[str, RawConfigDir]
 
 
-class ConfigDict(TypedDict):
-    """Configuration map for vcspull after shorthands and variables resolved."""
+class _ConfigDictRequired(TypedDict):
+    """Required fields for resolved vcspull configuration entries."""
 
     vcs: VCSLiteral | None
     name: str
     path: pathlib.Path
     url: str
     workspace_root: str
-    remotes: NotRequired[GitSyncRemoteDict | None]
-    shell_command_after: NotRequired[list[str] | None]
+
+
+class _ConfigDictOptional(TypedDict, total=False):
+    """Optional fields for resolved vcspull configuration entries."""
+
+    remotes: GitSyncRemoteDict | None
+    shell_command_after: list[str] | None
+
+
+class ConfigDict(_ConfigDictRequired, _ConfigDictOptional):
+    """Configuration map for vcspull after shorthands and variables resolved."""
 
 
 ConfigDir = dict[str, ConfigDict]