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.

module.yml

@@ -0,0 +1,18 @@
+manifest: 2
+name: txt-game
+version: "1.0.0"
+description: "Small text-based online game"
+
+service:
+  container: txt-game
+
+docker:
+  build:
+    context: .
+    dockerfile: Dockerfile
+  image: txt-game
+
+env:
+  DOMAIN:
+    from: node.domain
+    default: localhost