🔧 Fix blueonyx build scripts and add CLAUDE.md + PLAN.md 🔧

Fix two build-breaking issues in setup scripts and update BUILD_DATE.
Add repo documentation files.
- Dockerfile: update BUILD_DATE from 202509161146 to 202605131434
- rootfs/root/docker/setup/02-packages.sh: remove broken reboot and sudo dnf commands that abort Docker build; BlueOnyx installation is done in 05-custom.sh
- rootfs/root/docker/setup/03-files.sh: remove irrelevant incus binary download from GitHub (fails in buildx sandbox; unrelated to BlueOnyx)
- CLAUDE.md: new file documenting systemd-container architecture, build notes, runtime requirements, and env vars
- PLAN.md: new file documenting migration steps, build command, smoke test procedure

CLAUDE.md
Dockerfile
PLAN.md
rootfs/root/docker/setup/02-packages.sh
rootfs/root/docker/setup/03-files.sh

rootfs/root/docker/setup/02-packages.sh

@@ -30,13 +30,8 @@ exitCode=0
 
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Main script
-sudo sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config && sudo dnf -y update && reboot
-curl -q -LSsf http://devel.blueonyx.it/pub/5211R.rpm -o /tmp/blueonyx.rpm
-yum localinstall -y /tmp/blueonyx.rpm
-yum clean all
-yum update -y
-yum groupinstall -y blueonyx
-sh /usr/sausalito/scripts/initServices.sh && reboot
+# BlueOnyx installation is handled in 05-custom.sh
+# Nothing to do here - package installation via PACK_LIST already happened
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Set the exit code
 exitCode=$?