feat: add ArgoCD application configuration

- Add ArgoCD Application manifest for GitOps deployment
- Update image pull secret with actual Gitea credentials
- Enable automated sync with auto-prune and self-heal
- Configure namespace as adopt-a-street with auto-creation
- Add retry logic with exponential backoff for reliability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

argocd/application.yaml

@@ -0,0 +1,30 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: adopt-a-street
+  namespace: argocd
+  labels:
+    app: adopt-a-street
+spec:
+  destination:
+    namespace: adopt-a-street
+    server: https://kubernetes.default.svc
+  project: default
+  source:
+    path: deploy/k8s
+    repoURL: git@gitea-gitea-ssh.taildb3494.ts.net:will/adopt-a-street.git
+    targetRevision: main
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: true
+      allowEmpty: false
+    syncOptions:
+    - CreateNamespace=true
+    - ServerSideApply=true
+    retry:
+      limit: 5
+      backoff:
+        duration: 5s
+        factor: 2
+        maxDuration: 3m