feat: certificate page for print, API certificate data, AI prompts for full lessons

- Certificate: page /certificate/[courseId] with print-friendly design, GET /certificates/:courseId/data
- Buttons 'Получить сертификат' open certificate page instead of data-URL
- AI: prompts for longer courses (more chapters/lessons), full detailed lesson content with examples (1000–1500+ words)

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/src/lib/api.ts

@@ -299,6 +299,12 @@ class ApiClient {
     return this.request<{ certificateUrl: string; html: string }>(`/certificates/${courseId}`);
   }
 
+  async getCertificateData(courseId: string) {
+    return this.request<{ userName: string; courseTitle: string; completedAt: string }>(
+      `/certificates/${courseId}/data`
+    );
+  }
+
   // Search
   async searchCourses(query: string, filters?: { category?: string; difficulty?: string }) {
     const searchParams = new URLSearchParams({ q: query });