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/argocd.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: argocd
+  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: argocd
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: argocd
+  # NO syncPolicy.automated — manual sync required.
+  # Argo CD managing itself auto-synced is a footgun: a misconfigured commit could
+  # take down the CD system before anyone can intervene. Approve manually.