Add MCP servers (Gitea, K8s, Postgres, filesystem, git) to harness agents

Wire 5 MCP servers into Claude Code agents spawned by the harness:
- Gitea MCP for repo/issue/PR management on self-hosted Gitea
- Kubernetes MCP with read-only RBAC for cluster inspection
- Postgres MCP with read-only user for database queries
- Filesystem and Git MCP scoped to task worktrees

Generates .claude/settings.json in each worktree before agent spawn.
Gracefully skips for Codex/OpenCode runtimes (no MCP support).

Also fixes node-pty build failure by using local Node.js headers
instead of downloading from unofficial-builds.nodejs.org (ECONNRESET).

apps/harness/k8s/base/rbac.yaml

@@ -0,0 +1,35 @@
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: harness
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: harness-k8s-reader
+rules:
+  - apiGroups: [""]
+    resources: ["pods", "pods/log", "services", "configmaps", "namespaces", "events"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: ["apps"]
+    resources: ["deployments", "statefulsets", "daemonsets", "replicasets"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: ["batch"]
+    resources: ["jobs", "cronjobs"]
+    verbs: ["get", "list", "watch"]
+  - apiGroups: ["networking.k8s.io"]
+    resources: ["ingresses"]
+    verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: harness-k8s-reader
+subjects:
+  - kind: ServiceAccount
+    name: harness
+    namespace: apps
+roleRef:
+  kind: ClusterRole
+  name: harness-k8s-reader
+  apiGroup: rbac.authorization.k8s.io