feat : base url

README.md

@@ -57,7 +57,8 @@ cp .env.example .env
 
 `.env.example` contains placeholders only. Configure `.env` yourself; it is
 ignored by Git and must never be committed. `BETTER_AUTH_URL` must exactly
-match the application origin. Existing administrators can create additional
+match the application origin. Set `BASE_URL` to the public site origin for SEO
+metadata, sitemap, and robots.txt. Existing administrators can create additional
 credential accounts from `/admin/register`; public registration is disabled.
 
 Prepare the database and start the application:
@@ -153,6 +154,7 @@ with the same identity.
 ```bash
 docker build \
   --target app \
+  --build-arg BASE_URL=https://guide.sudloh.com \
   --build-arg NEXT_DEPLOYMENT_ID=<immutable-revision> \
   --build-arg VCS_REF=<immutable-revision> \
   --tag buzz-sheet:<immutable-revision> \
@@ -166,6 +168,9 @@ docker build \
 ```
 
 The runtime images do not contain local `.env` files.
+`BASE_URL` is required during the Next.js build and at runtime. CI supplies the
+build argument, and the Kubernetes ConfigMap supplies the runtime value. Keep
+both values aligned when changing the public site origin.
 
 ## Kubernetes