feat(headscale): add self-hosted Tailscale control server stack

CLI-managed (no web UI), sqlite-backed, fronted by Traefik like the other stacks.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

headscale/compose.yml

@@ -0,0 +1,37 @@
+services:
+  headscale:
+    image: headscale/headscale:latest
+    container_name: headscale
+    command: ["serve"]
+    environment:
+      TZ: ${TIMEZONE:-Europe/Amsterdam}
+      HEADSCALE_SERVER_URL: https://${TRAEFIK_HOST}
+    volumes:
+      - ./config.yaml:/etc/headscale/config.yaml:ro
+      - ../.data/headscale/data:/var/lib/headscale
+      - ../.data/headscale/run:/var/run/headscale
+    restart: always
+    healthcheck:
+      test: ["CMD", "/ko-app/headscale", "health"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 10s
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.middlewares.headscale-redirect-web-secure.redirectscheme.scheme=https"
+      - "traefik.http.routers.headscale-web.middlewares=headscale-redirect-web-secure"
+      - "traefik.http.routers.headscale-web.rule=Host(`${TRAEFIK_HOST}`)"
+      - "traefik.http.routers.headscale-web.entrypoints=web"
+      - "traefik.http.routers.headscale-web-secure.rule=Host(`${TRAEFIK_HOST}`)"
+      - "traefik.http.routers.headscale-web-secure.tls.certresolver=resolver"
+      - "traefik.http.routers.headscale-web-secure.entrypoints=web-secure"
+      - "traefik.http.routers.headscale-web-secure.middlewares=security-headers@file,no-index@file"
+      - "traefik.http.services.headscale-web-secure.loadbalancer.server.port=8080"
+      - "traefik.docker.network=${NETWORK_NAME}"
+    networks:
+      - compose_network
+networks:
+  compose_network:
+    name: ${NETWORK_NAME}
+    external: true