ver. 0.278: Settings + Languages frontend migration, bug fix get_single_settings_value

- Add cached frontend methods to existing Domain repositories (allSettings, getSingleValue, defaultLanguage, activeLanguages, translations)
- Convert front\factory\Settings and Languages to facades delegating to Domain repositories
- Fix get_single_settings_value() - was hardcoded to 'firm_name', now uses $param correctly
- Add CacheHandler stub methods (get/set/exists) to test bootstrap
- Establish architectural rule: Domain classes are shared between admin and frontend

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/CHANGELOG.md

@@ -4,6 +4,21 @@ Logi zmian z migracji na Domain-Driven Architecture. Najnowsze na gorze.
 
 ---
 
+## ver. 0.278 (2026-02-16) - Settings + Languages frontend migration
+
+- **Settings + Languages (frontend)** — pierwszy etap refaktoringu frontendu
+  - NOWE METODY: `SettingsRepository::allSettings($skipCache)` — pobranie ustawien z cache Redis
+  - NOWE METODY: `SettingsRepository::getSingleValue($param)` — pobranie pojedynczej wartosci ustawienia
+  - NOWE METODY: `LanguagesRepository::defaultLanguage()` — domyslny jezyk z cache Redis
+  - NOWE METODY: `LanguagesRepository::activeLanguages()` — lista aktywnych jezykow z cache Redis
+  - NOWE METODY: `LanguagesRepository::translations($lang)` — tlumaczenia z cache Redis
+  - UPDATE: `front\factory\Settings` → fasada delegujaca do `SettingsRepository`
+  - UPDATE: `front\factory\Languages` → fasada delegujaca do `LanguagesRepository`
+  - FIX: `get_single_settings_value()` — parametr `$param` poprawnie uzywany (wczesniej hardcoded `'firm_name'`)
+  - Testy: 427 OK, 1378 asercji (+13 nowych)
+
+---
+
 ## ver. 0.277 (2026-02-16) - ShopProduct factory, Dashboard, Update, legacy cleanup, admin\App
 
 - **ShopProduct (factory)** - pelna migracja modulu #29 na Domain + DI