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

cmd/edgeguard-api/main.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/gin-gonic/gin"
+)
+
+var version = "0.0.1-dev"
+
+func main() {
+	gin.SetMode(gin.ReleaseMode)
+	r := gin.New()
+	r.Use(gin.Recovery())
+
+	r.GET("/api/health", func(c *gin.Context) {
+		c.JSON(http.StatusOK, gin.H{"status": "ok", "version": version})
+	})
+
+	addr := os.Getenv("EDGEGUARD_API_ADDR")
+	if addr == "" {
+		addr = "127.0.0.1:9443"
+	}
+
+	log.Printf("edgeguard-api %s listening on %s", version, addr)
+	if err := r.Run(addr); err != nil {
+		log.Fatalf("edgeguard-api: %v", err)
+	}
+}