Grant deployer Ingress rights in its own namespace, for custom domains

Overdue: this belongs with toolshed's custom-domains feature, which has
already merged and shipped. Without it, deployer gets "forbidden" the
moment anyone actually adds a custom domain — the exact failure mode
internal/deploy/kubernetes.go's own package doc warns about, since its
resource list and this file are unsynchronised copies in two repositories.

Scoped as a namespaced Role/RoleBinding rather than widening the
ClusterRole above it. A custom domain's Ingress and TLS secret live in the
gateway's own namespace and never in an app's, so this only ever targets
one fixed namespace — unlike the per-app namespaces the ClusterRole
necessarily spans. Secrets are get/list/watch/delete only: cert-manager
writes them, deployer just reads readiness and cleans up on removal.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wajog7nELA3i8JWTjxYGHF

extra-manifests/toolshed-deployer-rbac.yaml

@@ -85,3 +85,47 @@ roleRef:
   apiGroup: rbac.authorization.k8s.io
   kind: ClusterRole
   name: toolshed-deployer
+---
+# A custom domain's Ingress and TLS secret live in the gateway's own
+# namespace (toolshed, same as above) — never an app's namespace. Scoped
+# with a namespaced Role/RoleBinding rather than widening the ClusterRole
+# above: Ingress management here only ever targets this one fixed
+# namespace, unlike the per-app namespaces the ClusterRole necessarily
+# spans. Added alongside toolshed's custom-domains feature — see
+# internal/deploy.Client.EnsureDomainIngress/DomainCertReady/
+# RemoveDomainIngress and this file's own header comment about keeping it
+# and deploy/helm/toolshed/templates/rbac.yaml in sync.
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: toolshed-deployer-ingress
+  namespace: toolshed
+  labels:
+    app.kubernetes.io/part-of: toolshed
+rules:
+  - apiGroups: ["networking.k8s.io"]
+    resources: ["ingresses"]
+    verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
+  # Reads the TLS secret cert-manager's ingress-shim populates for a domain
+  # Ingress, and deletes it (and the Ingress above) when a domain is
+  # removed. Never create/update — cert-manager, not deployer, writes this
+  # secret.
+  - apiGroups: [""]
+    resources: ["secrets"]
+    verbs: ["get", "list", "watch", "delete"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: toolshed-deployer-ingress
+  namespace: toolshed
+  labels:
+    app.kubernetes.io/part-of: toolshed
+subjects:
+  - kind: ServiceAccount
+    name: toolshed-deployer
+    namespace: toolshed
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: toolshed-deployer-ingress