chore: initial skeleton

- docs/architecture.md: native rewrite plan (5 services + control plane,
  Active-Active cluster like nmg, Floating-IP for HTTP ingress)
- cmd/edgeguard-{api,scheduler,ctl}: minimal Gin + CLI stubs
- packaging/debian/edgeguard-{api,ui,meta}: control + maintainer scripts
- deploy/systemd/edgeguard-api.service + edgeguard-scheduler.service
  with hardening defaults
- Makefile: build / cross-compile (amd64+arm64) / deb / publish targets
- scripts/install.sh + scripts/apt-repo/build-package.sh stubs

scripts/apt-repo/build-package.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Build .deb packages for EdgeGuard.
+# Usage: build-package.sh <amd64|arm64> <version>
+# Output: build/deb/edgeguard-{api,ui,meta}_<version>_<arch>.deb
+#
+# TODO — Stub. Wird mit Task #3 (Spike-Build) implementiert.
+set -euo pipefail
+ARCH="${1:?arch required}"
+VERSION="${2:?version required}"
+echo "build-package.sh stub — would build edgeguard-{api,ui,meta}_${VERSION}_${ARCH}.deb"