feat: scaffold Arcline OS build system

Scaffold the Arcline OS build system ("the wires"): a transparent,
auditable pipeline that turns a Debian bookworm base into hardened OS
images for the server, workstation, and cloud editions.

- Makefile orchestrates everything (make iso-<edition>, check, test,
  toolchain, clean); versions.mk is the single source of truth for
  versions and paths.
- scripts/ is the plain-bash pipeline: debootstrap -> install packages
  -> apply overlays -> in-chroot configure -> live ISO, plus a rootfs
  archive along the way.
- ARCLINE_TOOLCHAIN=auto|skip|require controls whether the 11 Go tools
  are bundled into an image (auto by default; minimal builds available
  via make iso-<edition>-minimal).
- GPL-3.0 licensed, sponsored by Arcline IT LLC.

scripts/build-edition.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────────────────────
+# Arcline OS — edition build orchestrator
+#
+#   scripts/build-edition.sh <edition> <stage>
+#     stage: rootfs | iso
+#
+# Thin dispatcher so the Makefile can stay dumb.
+# ─────────────────────────────────────────────────────────────────────────────
+set -euo pipefail
+source "$(dirname "${BASH_SOURCE[0]}")/common.sh"
+
+EDITION="${1:?usage: build-edition.sh <edition> <rootfs|iso>}"
+STAGE="${2:?usage: build-edition.sh <edition> <rootfs|iso>}"
+validate_edition "$EDITION"
+
+case "$STAGE" in
+  rootfs)
+    "$ROOT/scripts/build-rootfs.sh" "$EDITION"
+    ;;
+  iso)
+    "$ROOT/scripts/build-iso.sh" "$EDITION"
+    ;;
+  *)
+    die "unknown stage '$STAGE' (expected: rootfs | iso)"
+    ;;
+esac