feat(i18n): add French language support and enhance localization

- Introduced French as a supported language across the application, updating locale files and adding translations for various components.
- Enhanced language handling logic to accommodate French, ensuring proper detection and fallback mechanisms.
- Updated UI elements to include French language options, improving accessibility for French-speaking users.
- Refactored SEO handling to include French in hreflang links, enhancing search engine indexing for multilingual content.
- Added new scripts for managing French translations and ensuring consistency across language files.

frontend/src/views/falukant/FamilyView.vue

@@ -5,7 +5,7 @@
             <div class="family-content">
             <section class="family-hero surface-card">
                 <div>
-                    <span class="family-kicker">Familie</span>
+                    <span class="family-kicker">{{ $t('falukant.family.title') }}</span>
                     <h2>{{ $t('falukant.family.title') }}</h2>
                     <p>{{ $t('falukant.family.heroIntro') }}</p>
                 </div>