Add Docker deployment for mcwaddams.mcp.website

Multi-stage build: Node 22 for Astro build, Caddy 2 Alpine for
static file serving. Reverse-proxied via caddy-docker-proxy.

Makefile

@@ -0,0 +1,28 @@
+.PHONY: build up down restart logs status clean
+
+build:
+	docker compose build
+
+up: build
+	docker compose up -d
+	@echo "Waiting for container to start..."
+	@sleep 3
+	docker compose logs --tail=20
+
+down:
+	docker compose down
+
+restart:
+	docker compose down
+	docker compose up -d --build
+	@sleep 3
+	docker compose logs --tail=20
+
+logs:
+	docker compose logs -f
+
+status:
+	docker compose ps
+
+clean:
+	docker compose down --rmi local --volumes