Update builder id and remove src

build/Dockerfile

@@ -5,7 +5,12 @@ RUN pacman -Syu --noconfirm && \
     pacman -S --noconfirm base-devel git sudo wget jq gnupg
 
 # Create build user (required for makepkg)
-RUN useradd -m -G wheel builder && \
+# Note: UID/GID can be overridden at runtime via --build-arg
+ARG BUILD_UID=1000
+ARG BUILD_GID=1000
+
+RUN groupadd -g ${BUILD_GID} builder && \
+    useradd -m -u ${BUILD_UID} -g ${BUILD_GID} -G wheel builder && \
     echo "builder ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
 
 USER builder