feat: initial commit — void-installer multi-profile (stable-cinnamon + mainline-niri)

iso/Dockerfile

@@ -0,0 +1,19 @@
+# Container used to run void-mklive with real root.
+# This avoids the user-namespace CAP_MKNOD wall (dracut needs mknod /dev/null
+# inside the initramfs staging dir) and lets losetup/mount/chroot work
+# unconditionally. Host stays clean — no sudo, no host package installs.
+
+FROM debian:stable-slim
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        bash git curl ca-certificates xz-utils tar patch python3 \
+        mtools xorriso squashfs-tools dosfstools e2fsprogs \
+        kmod \
+    && rm -rf /var/lib/apt/lists/*
+
+# xbps-static is downloaded into /cache by the host script and added to PATH
+# at runtime by /work/iso/_inner-build.sh — no Void packages baked here.
+
+WORKDIR /work