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/config/keywordStrategy.ts

@@ -0,0 +1,58 @@
+import { Locale, LocaleKeywords } from '../types';
+
+/**
+ * Keyword Strategy Configuration
+ * Defines how keywords should be used across the site
+ */
+
+export const keywordStrategy = {
+  density: {
+    min: 0.5,      // 0.5% minimum keyword density
+    max: 2.5,      // 2.5% maximum (avoid keyword stuffing)
+    optimal: 1.5   // 1.5% optimal density
+  },
+  
+  placement: {
+    title: true,           // Include keyword in page title
+    h1: true,              // Include keyword in H1
+    h2: true,              // Include in at least one H2
+    firstParagraph: true,  // Include in first 100 words
+    metaDescription: true, // Include in meta description
+    altText: true          // Include in image alt text where relevant
+  },
+  
+  variations: true,        // Use keyword variations/synonyms
+  
+  // Meta title/descriptions character limits
+  metaLimits: {
+    titleMin: 30,
+    titleMax: 60,
+    descriptionMin: 120,
+    descriptionMax: 160
+  }
+};
+
+/**
+ * Get keyword usage recommendations for a page
+ */
+export function getKeywordRecommendations(
+  pageType: keyof LocaleKeywords['pages'],
+  locale: Locale
+): { primary: string[]; secondary: string[]; recommendations: string[] } {
+  const recommendations: string[] = [
+    `Use primary keywords within first 100 words`,
+    `Include at least one primary keyword in H1`,
+    `Meta title should be ${keywordStrategy.metaLimits.titleMin}-${keywordStrategy.metaLimits.titleMax} characters`,
+    `Meta description should be ${keywordStrategy.metaLimits.descriptionMin}-${keywordStrategy.metaLimits.descriptionMax} characters`,
+    `Maintain ${keywordStrategy.density.optimal}% keyword density`,
+    `Use keyword variations naturally throughout content`
+  ];
+
+  return {
+    primary: [], // Will be populated by getKeywords
+    secondary: [], // Will be populated by getKeywords
+    recommendations
+  };
+}
+
+export default keywordStrategy;