Add Gitea self-hosted git/CI/registry to replace GitHub

Deploy Gitea via Helm with dedicated CloudNativePG database,
in-cluster Actions runner (DinD), and built-in container registry.
ArgoCD repoURLs updated to use in-cluster Gitea SSH. Preview
ApplicationSet switched from GitHub PR generator to Gitea PR
generator. App images now pull from gitea.coreworlds.io registry.

Remaining setup after deploy: seal runner token, ArgoCD API token,
and registry pull secret once Gitea is running. Add ArgoCD deploy
key to Gitea repo settings.

apps/harness/k8s/base/deployment.yaml

@@ -15,10 +15,10 @@ spec:
         app: harness
     spec:
       imagePullSecrets:
-        - name: ghcr-pull-secret
+        - name: gitea-pull-secret
       containers:
         - name: harness
-          image: ghcr.io/lazorgurl/homelab-harness:latest
+          image: gitea.coreworlds.io/julia/homelab-harness:latest
           ports:
             - containerPort: 3100
           env:

apps/harness/k8s/overlays/production/kustomization.yaml

@@ -14,6 +14,6 @@ patches:
     kind: Deployment
     name: harness
 images:
-- name: ghcr.io/lazorgurl/homelab-harness
-  newName: ghcr.io/lazorgurl/homelab-harness
+- name: gitea.coreworlds.io/julia/homelab-harness
+  newName: gitea.coreworlds.io/julia/homelab-harness
   newTag: latest