Description

• Adds get_locale_string_from_xaml(xaml_base_path, key) to applocales.py —
  resolves a string from a *.ResourceDictionary.{locale}.xaml file with the
  same locale-then-English-then-key fallback as get_locale_string
• Removes the manual load_resource_string / get_translated_ui_string
  functions from Preflight Checks and replaces them with the new helper
• Replaces three WPFWindow temp-form constructions in Section Box Navigator
  __main__ (used only to call get_locale_string before the real form opens)
  with a lightweight _t() closure; tightens the surrounding error handling

EDIT:

refactor(preflight-checks): replace check_translations with applocales helper

• Removes check_translations.py — the module that used a hardcoded cross-bundle path to read locale strings from the pushbutton folder
• All check-specific strings now live in checks/locale/Checks.ResourceDictionary.{locale}.xaml, read via the existing applocales.get_locale_string_from_xaml helper (DRY — same API already used everywhere else in this branch)
• Pushbutton ResourceDictionary files are trimmed to the four strings they actually own (the selection dialog UI); check output strings no longer live there
• DocstringMeta metaclass replaced by plain name = _t(...) class attributes and ModelChecker.doc = _t(...) — same evaluation timing, zero magic
• Fixes extensions.components.get_checks() to filter .py files only, preventing IronPython from trying to compile XAML assets found in checks/

Checklist

Before submitting your pull request, ensure the following requirements are met:

• Code follows the PEP 8 style guide.
• Code has been formatted with Black using the command:

  pipenv run black {source_file_or_directory}

• Changes are tested and verified to work as expected.