🔧 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/03-files.sh

@@ -81,12 +81,6 @@ fi
 unset data
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Main script
-case $(uname -m) in
-"x86_64") target="bin.linux.incus.x86_64" ;;
-"aarch64") target="bin.linux.incus.aarch64" ;;
-*) target="bin.linux.incus.x86_64" ;;
-esac
-curl -q -LSsf "https://github.com/lxc/incus/releases/latest/download/$target" -o /usr/local/bin/incus && chmod 755 "/usr/local/bin/incus"
 # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 # Set the exit code
 exitCode=$?