feat(txt-game): initial module scaffold

Number guessing game (1-100, 7 attempts) as a HAL custom-app module.
Serves HTML form UI with per-session state via cookie, no npm deps.
Traefik labels for txt.${DOMAIN} on websecure with letsencrypt TLS.

.gitignore

@@ -0,0 +1,6 @@
+node_modules/
+.env
+.env.*
+*.log
+dist/
+.DS_Store