Replace storage:link with explicit ln -sf to fix broken symlink

php artisan storage:link was creating a regular file instead of a
symlink, causing 404s for all uploaded images.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/entrypoint.sh

@@ -27,7 +27,8 @@ mkdir -p storage/app/public \
          storage/framework/cache/data
 
 echo "==> Storage-Symlink anlegen..."
-php artisan storage:link --force
+rm -rf public/storage
+ln -sf ../storage/app/public public/storage
 
 echo "==> Cache für Produktion bauen..."
 php artisan config:cache