Deploy Forgejo on railiance01 using gitea-charts/gitea 12.5.0

Pin chart to 12.5.0 because 12.6+ calls `gitea config edit-ini`, which
Forgejo 11 lacks. Ingress targets forgejo-gitea-http (Helm release naming).
Smoke test uses GET for /v2/ registry challenge (HEAD returns 405).

helm/forgejo-registry-values.yaml

@@ -0,0 +1,14 @@
+# Public endpoint and package registry settings for Forgejo on railiance01.
+service:
+  http:
+    type: ClusterIP
+
+gitea:
+  config:
+    packages:
+      ENABLED: true
+      LIMIT_SIZE_CONTAINER: -1
+    repository:
+      DISABLED_REPO_UNITS: ""
+    server:
+      ROOT_URL: "https://forgejo.coulomb.social/"