tools/dev-deploy: long-lived dev environment behind host Caddy

A docker-compose stack that hosts postgres, redis, mailpit, backend,
gateway, and an app-routing Caddy. Reachable through the host Caddy at
https://www.galaxy.lan (static SPA) and https://api.galaxy.lan (REST +
gRPC). Coexists with tools/local-dev/ and tools/local-ci/ by giving
every name (compose project, container, network, volume) a distinct
galaxy-dev-* prefix.

State is persisted in named volumes; game-state lives under
${GALAXY_DEV_GAME_STATE_DIR:-$HOME/.galaxy-dev/game-state} so the
default works for a non-root runner without sudo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tools/dev-deploy/Caddyfile.prod

@@ -0,0 +1,15 @@
+# Production placeholder. Mirrors `Caddyfile.dev` but uses real
+# hostnames and lets Caddy auto-provision TLS certificates. Not used
+# until prod-deploy plumbing exists; kept under version control so the
+# dev/prod surface stays symmetric.
+
+www.galaxy.com {
+    root * /srv/galaxy-ui
+    try_files {path} /index.html
+    file_server
+    encode zstd gzip
+}
+
+api.galaxy.com {
+    reverse_proxy galaxy-api:8080
+}