Fix ARM64 archiso install: copy files directly, skip man page build

'make install' fails because rst2man (python-docutils) is not installed
and we don't need man pages in a container. Manually install just the
three things mkarchiso needs: the mkarchiso script, run_archiso, and
the configs directory.

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

iso/docker/Dockerfile.arm64

@@ -56,9 +56,13 @@ RUN pacman -Syu --noconfirm && \
     && pacman -Scc --noconfirm
 
 # Install archiso from upstream source (not packaged for aarch64 in ALARM).
-# PREFIX=/usr so mkarchiso lands in /usr/bin alongside pacman-installed tools.
+# Manually copy the three things mkarchiso needs — skip 'make install' because
+# it tries to build man pages with rst2man which isn't available.
 RUN git clone --depth=1 https://gitlab.archlinux.org/archlinux/archiso.git /tmp/archiso && \
-    make -C /tmp/archiso PREFIX=/usr install && \
+    install -Dm755 /tmp/archiso/archiso/mkarchiso   /usr/bin/mkarchiso && \
+    install -Dm755 /tmp/archiso/scripts/run_archiso.sh /usr/bin/run_archiso && \
+    install -d /usr/share/archiso && \
+    cp -a /tmp/archiso/configs /usr/share/archiso/ && \
     rm -rf /tmp/archiso
 
 WORKDIR /orionos