feat: add TLDR ArgumentAction and Rich-compatible prompt styling

- Introduce `ArgumentAction.TLDR` for showing concise usage examples
- Add `rich_text_to_prompt_text()` to support Rich-style markup in all prompt_toolkit inputs
- Migrate all prompt-based Actions to use `prompt_message` with Rich styling support
- Standardize `CancelSignal` as the default interrupt behavior for prompt-driven Actions

tests/test_parsers/test_argument_action.py

@@ -8,4 +8,4 @@ def test_argument_action():
     assert action != "invalid_action"
     assert action.value == "append"
     assert str(action) == "append"
-    assert len(ArgumentAction.choices()) == 9
+    assert len(ArgumentAction.choices()) == 10