feat: add Gitea CI workflows and split deploy manifests

Add build and kubernetes-deploy Gitea Actions workflows, and split deploy/manifests.yaml into individual manifest files.

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

deploy/clusterrole_gateway-cert-operator.yaml

@@ -0,0 +1,20 @@
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: gateway-cert-operator
+  labels:
+    app.kubernetes.io/name: gateway-cert-operator
+    app.kubernetes.io/component: operator
+rules:
+  # Watch and read Certificates
+  - apiGroups: ["cert-manager.io"]
+    resources: ["certificates"]
+    verbs: ["get", "list", "watch"]
+  # Read and patch Gateways
+  - apiGroups: ["gateway.networking.k8s.io"]
+    resources: ["gateways"]
+    verbs: ["get", "list", "watch", "patch"]
+  # Emit events
+  - apiGroups: [""]
+    resources: ["events"]
+    verbs: ["create", "patch"]