Add web admin features + fix scraper & translator

Frontend changes:
- Add /admin dashboard for article management
- Add AdminButton component (Alt+Shift+A on articles)
- Add /api/admin/article API endpoints

Backend improvements:
- scraper_v2.py: Multi-layer fallback extraction (newspaper → trafilatura → readability)
- translator_v2.py: Better chunking, repetition detection, validation
- admin_tools.py: CLI admin commands
- test_scraper.py: Individual source testing

Docs:
- WEB-ADMIN-GUIDE.md: Web admin usage
- ADMIN-GUIDE.md: CLI admin usage
- SCRAPER-IMPROVEMENT-PLAN.md: Scraper fixes details
- TRANSLATION-FIX.md: Translation improvements
- ADMIN-FEATURES-SUMMARY.md: Implementation summary

Fixes:
- Article scraping from 0 → 96+ articles working
- Translation quality issues (repetition, truncation)
- Added 13 new RSS sources

frontend/app/article/[slug]/page.tsx

@@ -3,6 +3,7 @@ export const dynamic = "force-dynamic"
 import { notFound } from 'next/navigation'
 import Link from 'next/link'
 import Image from 'next/image'
+import AdminButton from '@/components/AdminButton'
 
 async function getArticleWithTags(slug: string) {
   try {
@@ -267,6 +268,9 @@ export default async function ImprovedArticlePage({ params }: { params: { slug:
           </div>
         </section>
       )}
+
+      {/* Admin Button (hidden, press Alt+Shift+A to show) */}
+      <AdminButton articleId={article.id} articleTitle={article.title_burmese} />
     </div>
   )
 }