feat(providers): support SPIFFE-backed token grants

.agents/skills/debug-openshell-cluster/SKILL.md

@@ -172,6 +172,24 @@ If the gateway exits with `failed to read sandbox JWT signing key from
 `sandbox-jwt` secret at `/etc/openshell-jwt`. The sandbox JWT mount is required
 even when local Helm values disable TLS.
 
+If `server.providerTokenGrants.spiffe.enabled=true`, the gateway should still
+render `[openshell.gateway.gateway_jwt]` and mount the `sandbox-jwt` Secret.
+SPIRE is used only by sandbox pods for dynamic provider token grants. Verify
+that SPIRE is installed, the CSI driver is available, and the Kubernetes driver
+config includes `provider_spiffe_workload_api_socket_path`:
+
+```bash
+helm -n openshell get values openshell | grep -E 'providerTokenGrants|workloadApiSocketPath'
+kubectl get pods -A | grep -E 'spire|spiffe'
+kubectl -n openshell get configmap openshell-config -o yaml | grep provider_spiffe_workload_api_socket_path
+```
+
+Sandbox pods using provider token grants should have an
+`openshell.io/sandbox-id` annotation, an `openshell.ai/managed-by=openshell`
+label, supervisor env vars `OPENSHELL_K8S_SA_TOKEN_FILE` and
+`OPENSHELL_PROVIDER_SPIFFE_WORKLOAD_API_SOCKET`, plus both the projected
+`openshell-sa-token` volume and the `spiffe-workload-api` CSI volume.
+
 Check the image references currently used by the gateway deployment:
 
 ```bash

.agents/skills/helm-dev-environment/SKILL.md

@@ -177,6 +177,23 @@ To remove Keycloak:
 mise run keycloak:k8s:teardown
 ```
 
+### SPIRE / SPIFFE Provider Token Grants
+
+Skaffold can install SPIRE with the SPIFFE hardened Helm charts. To activate
+SPIFFE JWT-SVIDs for dynamic provider token grants:
+
+1. Uncomment the `spire-crds` and `spire` releases in `deploy/helm/openshell/skaffold.yaml`
+2. Uncomment `#- ci/values-spire.yaml` in the OpenShell release values files
+3. Redeploy: `mise run helm:skaffold:run`
+
+`ci/values-spire-stack.yaml` configures the local SPIRE trust domain as
+`openshell.local` and adds a `ClusterSPIFFEID` that maps sandbox pod
+annotations to `spiffe://openshell.local/openshell/sandbox/<sandbox-id>`.
+OpenShell mounts the SPIFFE CSI Workload API socket at
+`/spiffe-workload-api/spire-agent.sock` into sandbox pods for provider token
+grants. Supervisor-to-gateway authentication remains on the Kubernetes
+ServiceAccount bootstrap and gateway-minted sandbox JWT path.
+
 ---
 
 ## Cluster Lifecycle (suspend/resume)
@@ -205,6 +222,8 @@ mise run helm:k3s:status
 | `deploy/helm/openshell/ci/values-gateway.yaml` | Envoy Gateway GRPCRoute + Gateway overlay |
 | `deploy/helm/openshell/ci/values-high-availability.yaml` | HA test overlay (`replicaCount: 2` with bundled PostgreSQL) |
 | `deploy/helm/openshell/ci/values-keycloak.yaml` | Keycloak OIDC overlay |
+| `deploy/helm/openshell/ci/values-spire.yaml` | SPIFFE/SPIRE provider token grant overlay |
+| `deploy/helm/openshell/ci/values-spire-stack.yaml` | SPIRE hardened chart values for local dev |
 | `deploy/helm/openshell/ci/values-tls-disabled.yaml` | Lint-only: TLS + auth disabled (reverse-proxy edge termination) |
 | `deploy/kube/manifests/envoy-gateway-openshell.yaml` | GatewayClass for Envoy Gateway (`mise run helm:gateway:apply`) |
 | `tasks/scripts/helm-k3s-local.sh` | k3d cluster create/delete/start/stop/status |