feat(ops): add k3s + ArgoCD GitOps pipeline

- Dockerfile: copy web/ and assets/ to runtime stage so ServeDir routes work
- .gitea/workflows/docker-build.yml: build/push image on master push, pin SHA
  tag back into deploy/kustomization.yaml so ArgoCD sees a real manifest change
- deploy/: Kustomize manifests — Namespace, PVC, Deployment (Recreate for
  SQLite), Service, Traefik Ingress at klondike.aleshym.co
- argocd/application.yaml: auto-sync Application watching deploy/ on Gitea

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

deploy/kustomization.yaml

@@ -0,0 +1,16 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml
+  - pvc.yaml
+  - deployment.yaml
+  - service.yaml
+  - ingress.yaml
+
+# CI updates this block automatically via `kustomize edit set image`.
+# The image name here matches the `image: solitaire-server` stub in deployment.yaml.
+images:
+  - name: solitaire-server
+    newName: git.aleshym.co/funman300/solitaire-server
+    newTag: latest