k8s/ci-cd: add forgejo gitops and argocd deployment

- Forgejo git forge + OCI registry
- Argo CD pull-based GitOps
- Private CA TLS (self-signed 10-year cert)
- Machine credentials scoped to repositories

k8s/talos-ci-cd/deploy-scaffold/apps/forge.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: forge
+  namespace: argocd
+  annotations:
+    argocd.argoproj.io/sync-wave: "0"
+spec:
+  project: default
+  source:
+    repoURL: https://forgejo.forge.riotpiao.homelab.com/rock/deploy.git
+    targetRevision: main
+    path: forge
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: forge
+  # NO syncPolicy.automated — manual sync required.
+  # Forgejo is what CI uses to push commits; auto-sync would let a bad CI commit
+  # break the very system CI depends on. Approve syncs manually in the Argo CD UI.