feat: implement build-time patching system and fix libdir bug

- Adds a generic RUN step to apply all .patch files in the patches/ directory
- Includes 001--fix-moodle-5.1.3-libdir-initialization--20260307.patch
- Adds 'less' utility to base system packages for easier debugging

Author: hlfbt

Dockerfile

@@ -1,6 +1,8 @@
 ARG PHP_VERSION=8.4
 ARG MOODLE_VERSION=5.1.3
 ARG MOODLE_MAJOR_VERSION=501
+ARG ADDITIONAL_APT_PACKAGES=""
+ARG ADDITIONAL_PHP_EXTENSIONS=""
 
 FROM php:${PHP_VERSION}-fpm
 
@@ -19,6 +21,9 @@ RUN apt-get update && apt-get install -y \
     libz-dev \
     curl \
     gettext-base \
+    patch \
+    less \
+    ${ADDITIONAL_APT_PACKAGES} \
     && rm -rf /var/lib/apt/lists/*
 
 # Install PHP extensions using mlocati/php-extension-installer
@@ -36,7 +41,8 @@ RUN install-php-extensions \
     calendar \
     sockets \
     sodium \
-    redis
+    redis \
+    ${ADDITIONAL_PHP_EXTENSIONS}
 
 # Increase max_input_vars
 RUN echo "max_input_vars = 5000" >> /usr/local/etc/php/conf.d/docker-php-moodle.ini
@@ -57,12 +63,19 @@ RUN mkdir -p /var/www/moodledata \
 
 WORKDIR /var/www/html
 
-# Copy entrypoint, step scripts, helper scripts and templates to /opt/moodle
-# to prevent them from being shadowed by /var/www/html volume mounts
+# Copy entrypoint, step scripts, helper scripts, templates and patches to /opt/moodle
 COPY docker-entrypoint.sh /usr/local/bin/
 COPY scripts/ /opt/moodle/scripts/
 COPY entrypoint.d/ /docker-entrypoint.d/
 COPY templates/ /opt/moodle/templates/
+COPY patches/ /opt/moodle/patches/
+
+# Apply patches
+RUN for p in /opt/moodle/patches/*.patch; do \
+        [ -e "$p" ] || continue; \
+        echo "Applying patch $p"; \
+        patch -p0 < "$p"; \
+    done
 
 RUN chmod +x /usr/local/bin/docker-entrypoint.sh \
     && chmod +x /docker-entrypoint.d/*.sh \

patches/001--fix-moodle-5.1.3-libdir-initialization--20260307.patch

@@ -0,0 +1,9 @@
+--- lib/setup.php
++++ lib/setup.php
+@@ -24,5 +24,5 @@
+  */
+ 
+ if (property_exists($CFG, 'dirroot') && !str_ends_with($CFG->dirroot, '/public')) {
+-    $CFG->libdir = $CFG->libdir . '/lib';
++    $CFG->libdir = $CFG->dirroot . '/lib';
+ }