fix: resolve Decap CMS media 404s and add Turkish translations

- Fix Decap CMS configuration with proper media folder paths
- Add Turkish translations for sharing interface elements
- Implement smart background handling for transparent logos
- Update image path conversion system for CMS compatibility
- Add comprehensive image optimization with Astro assets
- Update all blog post image paths for consistency

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

public/_redirects

@@ -3,6 +3,5 @@
 /#recovery_token=* /auth?recovery_token=:splat 200
 /#invite_token=* /auth?invite_token=:splat 200
 
-# Admin panel redirect
-/admin/ /decapcms/index.html 200
-/admin/index.html /decapcms/index.html 200
+# Admin panel access
+/admin /admin/ 302