Add deployment infrastructure and TUI showcase guide

Dockerfile (multi-stage: base/dev/build/prod with caddy:2-alpine),
docker-compose.yml with caddy-docker-proxy labels for birdcage.warehack.ing,
Caddyfile, Makefile (up/down/dev/prod/clean), and .env.

TUI guide page with 4 screenshots (F1 position, F2 signal, F4 system,
F5 console), demo mode docs, and project backstory crediting Gabe Emerson
(KL1FI) and Chris Davidson.

docker-compose.yml

@@ -0,0 +1,31 @@
+services:
+  docs:
+    build:
+      context: .
+      target: ${APP_ENV:-dev}
+    container_name: birdcage-docs
+    restart: unless-stopped
+    environment:
+      - PUBLIC_DOMAIN=${PUBLIC_DOMAIN}
+      - VITE_HMR_HOST=${VITE_HMR_HOST}
+    networks:
+      - caddy
+    labels:
+      caddy: ${PUBLIC_DOMAIN}
+      caddy.reverse_proxy: "{{upstreams ${APP_PORT:-4321}}}"
+      caddy.reverse_proxy.flush_interval: "-1"
+      caddy.reverse_proxy.transport: http
+      caddy.reverse_proxy.transport.read_timeout: "0"
+      caddy.reverse_proxy.transport.write_timeout: "0"
+      caddy.reverse_proxy.transport.keepalive: 5m
+      caddy.reverse_proxy.transport.keepalive_idle_conns: "10"
+      caddy.reverse_proxy.stream_timeout: 24h
+      caddy.reverse_proxy.stream_close_delay: 5s
+    volumes:
+      - ./src:/app/src
+      - ./public:/app/public
+      - ./astro.config.mjs:/app/astro.config.mjs
+
+networks:
+  caddy:
+    external: true