feat: implement Dynamic Data Binding system and tags registry

src/utils/dynamicDataBinding.ts

@@ -0,0 +1,49 @@
+export interface DynamicFieldDefinition {
+  key: string; // e.g. 'site.siteName', 'post.title', 'custom.clientName'
+  label: string;
+  category: 'site' | 'post' | 'author' | 'custom';
+  defaultValue: string;
+}
+
+export const DYNAMIC_FIELDS_REGISTRY: DynamicFieldDefinition[] = [
+  { key: 'site.siteName', label: 'Website Name', category: 'site', defaultValue: 'N&D IT Solutions' },
+  { key: 'site.metaDescription', label: 'Website Beschreibung', category: 'site', defaultValue: 'High-Performance Webdesign & Digital Solutions' },
+  { key: 'site.contactEmail', label: 'Kontakt E-Mail', category: 'site', defaultValue: 'kontakt@ndsolutions.de' },
+  { key: 'site.phone', label: 'Telefonnummer', category: 'site', defaultValue: '+49 (0) 123 456789' },
+  { key: 'post.title', label: 'Beitragstitel (Dynamisch)', category: 'post', defaultValue: 'Beispiel Artikel' },
+  { key: 'post.excerpt', label: 'Beitrags Auszug', category: 'post', defaultValue: 'Ein kurzer Auszug des Artikels...' },
+  { key: 'author.name', label: 'Autor Name', category: 'author', defaultValue: 'N&D Team' }
+];
+
+/**
+ * Replaces dynamic binding tags like `{{site.siteName}}` or evaluates binding keys against a data context.
+ */
+export function resolveDynamicBinding(
+  content: string,
+  contextData: Record<string, any>
+): string {
+  if (!content) return content;
+  
+  return content.replace(/\{\{([^}]+)\}\}/g, (_, key) => {
+    const trimmedKey = key.trim();
+    const keys = trimmedKey.split('.');
+    let val: any = contextData;
+
+    for (const k of keys) {
+      if (val && typeof val === 'object' && k in val) {
+        val = val[k];
+      } else {
+        val = undefined;
+        break;
+      }
+    }
+
+    if (val !== undefined && val !== null) {
+      return String(val);
+    }
+
+    // Fallback to registry default if available
+    const regItem = DYNAMIC_FIELDS_REGISTRY.find(f => f.key === trimmedKey);
+    return regItem ? regItem.defaultValue : `{{${trimmedKey}}}`;
+  });
+}