Drop Xdebug install and xdebug.ini copy from Dockerfile

Completes bcaaf8e, which removed xdebug.ini but left the Dockerfile
still referencing it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -58,16 +58,9 @@ RUN pecl install channel://pecl.php.net/xmlrpc-1.0.0RC3 && docker-php-ext-enable
 # Optional: Install and enable Imagick (used by Moodle for better image processing)
 RUN pecl install imagick && docker-php-ext-enable imagick
 
-# Install Xdebug
-RUN pecl install xdebug \
-    && docker-php-ext-enable xdebug
-
 # Set recommended PHP configuration values for Moodle
 COPY moodle-php.ini /usr/local/etc/php/conf.d/moodle-php.ini
 
-# Copy custom php.ini
-COPY ./xdebug.ini /usr/local/etc/php/conf.d/xdebug.ini
-
 # Create moodledata directory
 RUN mkdir -p /var/www/moodledata && \
     chown -R www-data:www-data /var/www/moodledata && \