gitea: use git.k8s ROOT_URL for testing (#317)

Points the new gitea at its own k8s route so it can be exercised (login, browse, OIDC callback) before the git.unkin.net data cutover — ROOT_URL currently resolves to the live VM forge, which would break links on the k8s route. Flips back to git.unkin.net at cutover.

- set gitea DOMAIN/ROOT_URL/SSH_DOMAIN to git.k8s.syd1.au.unkin.net

Reviewed-on: #317
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

apps/overlays/au-syd1/gitea/values.yaml

@@ -125,9 +125,9 @@ gitea:
 
   config:
     server:
-      DOMAIN: git.unkin.net
-      ROOT_URL: https://git.unkin.net/
-      SSH_DOMAIN: git.unkin.net
+      DOMAIN: git.k8s.syd1.au.unkin.net
+      ROOT_URL: https://git.k8s.syd1.au.unkin.net/
+      SSH_DOMAIN: git.k8s.syd1.au.unkin.net
       DISABLE_SSH: true
       START_SSH_SERVER: false
       LFS_START_SERVER: true