pyproject.toml: Enforce import annotations style

Add new ruff rules and fix their fallout:

  future-annotations = true

   select = [
    "TC",  # type-checking import placement rules
    "FA",  # future annotations rules
   ]

This comprises:

  - Streamline imports and exports in cmds.xxx.Cmd

    - Import base class as "Base"

    - Export types Cmd and Parent via __all__

  - Move all types imported only for annotation below TYPE_CHECKING

  - Use "from __future__ import annotations" all over the place

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/util.py

@@ -4,7 +4,6 @@ import json
 import os
 import sys
 
-from argparse import Namespace
 from enum import Enum, auto
 from typing import TYPE_CHECKING, Iterable, TypeVar, cast
 
@@ -13,6 +12,7 @@ from .log import DEBUG, ERR, log
 from .Uri import Uri
 
 if TYPE_CHECKING:
+    from argparse import Namespace
     from .ExecContext import ExecContext
     from .FileContext import FileContext
     from .ProcFilter import ProcFilter, ProcPipeline
@@ -93,7 +93,7 @@ async def run_curl_into(
         raise TypeError(
             f'Expected {expected_type.__name__}, got {type(ret).__name__} from Curl'
         )
-    return cast(T, ret)
+    return cast('T', ret)
 
 async def run_askpass(
     askpass_env: list[str],