feat: comprehensive SEO system with keywords and schema markup

- Add 4-locale keyword configurations (SR, EN, DE, FR)
- Create schema generators (Product, Organization, Breadcrumb)
- Add React components for JSON-LD rendering
- Implement caching for keyword performance
- Abstract all SEO logic for maintainability

src/lib/seo/keywords/index.ts

@@ -0,0 +1,46 @@
+/**
+ * SEO Keywords Module
+ * Centralized, localized keyword management for SEO optimization
+ * 
+ * Usage:
+ * import { getKeywords, getPageKeywords, Locale } from '@/lib/seo/keywords';
+ * 
+ * const keywords = getKeywords('sr');
+ * const homeKeywords = getPageKeywords('sr', 'home');
+ */
+
+// Types
+export type { 
+  Locale, 
+  LocaleKeywords, 
+  BrandKeywords, 
+  PageKeywords, 
+  ProductCategoryKeywords,
+  ContentKeywords,
+  CompetitorKeywords,
+  KeywordStrategy 
+} from './types';
+
+// Main functions
+export { 
+  getKeywords,
+  getPageKeywords,
+  getCategoryKeywords,
+  getContentKeywords,
+  getCompetitorKeywords,
+  getBrandKeywords,
+  clearKeywordsCache,
+  getAvailableLocales,
+  isValidLocale
+} from './utils/getKeywords';
+
+// Keyword strategy
+export { keywordStrategy, getKeywordRecommendations } from './config/keywordStrategy';
+
+// Locale-specific exports (for direct access if needed)
+export { serbianKeywords } from './locales/sr';
+export { englishKeywords } from './locales/en';
+export { germanKeywords } from './locales/de';
+export { frenchKeywords } from './locales/fr';
+
+