refactor: keep list help in the literal help text blocks (#1327)

## ℹ️ Description

Follow-up to #1321. The CLI help text is the one place that keeps a
complete English and a complete German text block in the code, so `list`
belongs into both blocks instead of using a gettext lookup with a
temporary locale switch. Related issue: none.

## 📋 Changes Summary

- Write the `list` help line literally into the English and German
blocks of `help_text()` and drop the locale switch and the `help_text`
entry in `translations.de.yaml`.
- Replace the locale-preservation test with a simple check of the `list`
line per language.
- Document the exception for the CLI help text in `CONTRIBUTING.md`.

No dependencies or configuration changes.

### ⚙️ Type of Change

- [ ] 🐞 Bug fix (non-breaking change which fixes an issue)
- [ ] ✨ New feature (adds new functionality without breaking existing
usage)
- [ ] 💥 Breaking change (changes that might break existing user setups,
scripts, or configurations)

Refactoring only, no user-visible change: the help output is identical.

## ✅ Checklist

- [x] I have reviewed my changes to ensure they meet the project's
standards.
- [x] I have tested my changes and ensured that all tests pass (`pdm run
utest` locally, the full suite runs in CI).
- [x] I have formatted the code (`pdm run format`).
- [x] I have verified that linting passes (`pdm run lint`).
- [x] I have updated documentation where necessary.

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* CLI help now displays the complete English or German text for the
`list` command, regardless of the currently active language setting.
* **Documentation**
* Updated translation guidance to clarify that CLI help text should
include complete English and German wording.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

CONTRIBUTING.md

@@ -339,6 +339,6 @@ See the [LICENSE.txt](LICENSE.txt) file for our project's licensing. All source
 - For every user-facing message, a **German translation** must be added to `src/kleinanzeigen_bot/resources/translations.de.yaml`.
 - Log messages are auto-translated by `TranslatingLogger`; do not wrap `LOG.*`/`logger.*` message strings with `_()`.
 - Non-log user-facing strings (e.g., `print`, `ainput`, exceptions, validation messages) should use `_()`.
-- Use the translation system for all output—**never hardcode German or other languages** in the code.
+- Use the translation system for all output—**never hardcode German or other languages** in the code. The one exception is the CLI help text (`help_text()` in `cli.py`), which keeps a complete English and a complete German text block; add new commands and options to both blocks instead of using `_()`.
 - If you add or change a user-facing message, update the translation file and ensure that translation completeness tests pass (`tests/unit/test_translations.py`).
 - Review the translation guidelines and patterns in the codebase for correct usage.

src/kleinanzeigen_bot/cli.py

@@ -19,7 +19,6 @@ import signal
 import sys
 import textwrap
 from dataclasses import dataclass
-from gettext import gettext as _
 from pathlib import Path
 from typing import TYPE_CHECKING, Final
 
@@ -140,15 +139,8 @@ def _help_executable() -> str:
 
 
 def help_text(*, executable:str | None = None, language:str | None = None) -> str:
-    """Render CLI help in the requested language without changing the current locale."""
     exe = executable if executable is not None else _help_executable()
-    current_locale = get_current_locale()
-    lang = language if language is not None else current_locale.language
-    try:
-        set_current_locale(Locale(lang))
-        list_description = _("lists current online ads with ID, title, state, and expiry date")
-    finally:
-        set_current_locale(current_locale)
+    lang = language if language is not None else get_current_locale().language
     if lang == "de":
         return textwrap.dedent(
             f"""\
@@ -170,7 +162,7 @@ def help_text(*, executable:str | None = None, language:str | None = None) -> st
               create-config - Erstellt eine neue Standard-Konfigurationsdatei, falls noch nicht vorhanden
               diagnose - Diagnostiziert Browser-Verbindungsprobleme und zeigt Troubleshooting-Informationen
               status   - Zeigt Anzeigenstatus und APR-Vorschau an
-              list     - {list_description}
+              list     - Zeigt aktuelle Online-Anzeigen mit ID, Titel, Status und Ablaufdatum an
               --
               help     - Zeigt diese Hilfe an (Standardbefehl)
               version  - Zeigt die Version der Anwendung an
@@ -235,7 +227,7 @@ def help_text(*, executable:str | None = None, language:str | None = None) -> st
           create-config - creates a new default configuration file if one does not exist
           diagnose - diagnoses browser connection issues and shows troubleshooting information
           status   - shows ad status and APR preview details
-          list     - {list_description}
+          list     - lists current online ads with ID, title, state, and expiry date
           --
           help     - displays this help (default command)
           version  - displays the application version

src/kleinanzeigen_bot/resources/translations.de.yaml

@@ -30,9 +30,6 @@ kleinanzeigen_bot/captcha_flow.py:
 #################################################
 kleinanzeigen_bot/cli.py:
 #################################################
-  help_text:
-    "lists current online ads with ID, title, state, and expiry date": "Zeigt aktuelle Online-Anzeigen mit ID, Titel, Status und Ablaufdatum an"
-
   parse_args:
     "Use --help to display available options.": "Mit --help können die verfügbaren Optionen angezeigt werden."
     "Unknown command: %s": "Unbekannter Befehl: %s"

tests/unit/test_list_command.py

@@ -108,18 +108,13 @@ def test_list_is_accepted_and_documented() -> None:
     assert "list     -" in help_text(language = "de")
 
 
-@pytest.mark.parametrize("initial_language", ["en", "de"])
 @pytest.mark.parametrize(("language", "description"), [
     ("en", "lists current online ads with ID, title, state, and expiry date"),
     ("de", "Zeigt aktuelle Online-Anzeigen mit ID, Titel, Status und Ablaufdatum an"),
 ])
-def test_list_help_honors_explicit_language_and_preserves_locale(initial_language:str, language:str, description:str) -> None:
-    """Honor the requested help language without changing the caller locale."""
-    locale = i18n.Locale(initial_language, "TEST")
-    i18n.set_current_locale(locale)
-
+def test_list_help_is_rendered_in_requested_language(language:str, description:str) -> None:
+    """Describe the list command in the requested help language."""
     assert f"list     - {description}" in help_text(language = language)
-    assert i18n.get_current_locale() == locale
 
 
 @pytest.mark.asyncio