revert(phase4): Remove Pod Job approach for Terraform apply

Reverting Phase 4 Pod Job implementation in favor of CI runner (Forgejo Actions).

Deleted:
- k8s/argocd/apps/phase4-terraform-0.yaml
- k8s/hooks/phase4/ (terraform-apply-hook.yaml, terraform-rbac.yaml, terraform-s3-secrets.enc.yaml)

Reason: Pod Job approach had limitations (eviction, timeouts, pod security policies).
Next: Implement Forgejo Actions CI workflow for terraform apply.

k8s/argocd/apps/phase4-terraform-0.yaml

@@ -1,26 +0,0 @@
-# Phase 4 — IaC (Terraform) — infrastructure-as-code via Hook Job
-# ArgoCD-driven terraform apply. All changes via git push.
-
----
-apiVersion: argoproj.io/v1alpha1
-kind: Application
-metadata:
-  name: terraform-apply
-  namespace: argocd
-  annotations:
-    argocd.argoproj.io/sync-wave: "4"
-spec:
-  project: homelab
-  sources:
-    - repoURL: https://forgejo.riotpiao.homelab.com/riotpiao.com/homelab.git
-      targetRevision: main
-      path: k8s/hooks/phase4
-  destination:
-    server: https://kubernetes.default.svc
-    namespace: argocd
-  syncPolicy:
-    automated:
-      prune: true
-      selfHeal: true
-    syncOptions:
-      - CreateNamespace=true