prop: move ArgoCD source + image-updater to codeberg

The prop and prop-grid-rs container images now live on
codeberg.org/gmcintire/* (see prop repo commit 8a9c0ba6 for the
workflow flip). Application source repo and image-updater registry
list follow.

Cluster-side state still required for this to roll out, applied
out-of-band via kubectl:

- Secret prop/forgejo-registry — dockerconfigjson with codeberg.org
  auth (also keeps git.mcintire.me auth during the transition).
- Secret argocd/forgejo-registry — same shape, used by the
  argocd-image-updater registry config.
- Secret argocd/codeberg-credentials-gmcintire (label
  argocd.argoproj.io/secret-type=repo-creds) — credentials template
  matching url=https://codeberg.org/gmcintire so future codeberg
  repos under that owner pick up auth automatically.
- ConfigMap argocd/argocd-image-updater-config — registries.conf
  extended with codeberg.org entry referencing the new pull secret.

home/cluster/argocd/apps/prop.yaml

@@ -4,7 +4,7 @@ metadata:
   name: prop
   namespace: argocd
   annotations:
-    argocd-image-updater.argoproj.io/image-list: prop=git.mcintire.me/graham/prop,grid=git.mcintire.me/graham/prop-grid-rs
+    argocd-image-updater.argoproj.io/image-list: prop=codeberg.org/gmcintire/prop,grid=codeberg.org/gmcintire/prop-grid-rs
     argocd-image-updater.argoproj.io/prop.update-strategy: newest-build
     argocd-image-updater.argoproj.io/prop.allow-tags: regexp:^main-[0-9]+-[0-9a-f]+$
     argocd-image-updater.argoproj.io/grid.update-strategy: newest-build
@@ -15,7 +15,7 @@ metadata:
 spec:
   project: default
   source:
-    repoURL: https://git.mcintire.me/graham/prop.git
+    repoURL: https://codeberg.org/gmcintire/prop.git
     targetRevision: main
     path: k8s
   destination: