Merge origin/l10n_main (PR #428) with a per-key three-way resolution:
Crowdin values win only where main did not change the key since the
last sync, so the unused-key removal, store->repo wording sweep, and
ICU plural fixes survive. Korean is restored at 98% completion and
mapped again in crowdin.yml and both language pickers; ar/hi/nl/zh-CN/
zh-TW stay dropped (37% and below).
Follow-up to the arb removal: unmap ar/hi/ko/nl/zh-CN/zh-TW in
crowdin.yml so crowdin pull does not recreate them, trim the dead
entries from both language pickers, and add the missing uk entry to
the setup-screen picker.
Map placeholders to the project's actual Crowdin language ids and drop the bogus bare keys (es, pt, zh) that aren't real Crowdin codes and broke crowdin-cli config validation. Add Arabic (ar) mapped to app_ar.arb so future syncs use underscore filenames instead of hyphenated ones (e.g. app_ar-SA.arb) that break Flutter gen-l10n.
- Change crowdin.yml to use %locale_with_underscore% for proper zh_CN/zh_TW handling
- Add sectionLanguage, appearanceLanguage, appearanceLanguageSubtitle to app_en.arb
- Add app_zh_CN.arb for Simplified Chinese (Crowdin target)
- Update .gitignore to exclude log files and tool/ folder
- Regenerate localization dart files
zarzet