feat: gsc-shell-api v0.1 — central chrome data API

Tiny Go service that returns ShellConfig JSON for any registered app.
Backs the runtime-loaded <AppShell> component being added to
@limitless/ui (next).

Endpoints:
  GET /api/v1/shell/{appKey}  → app + branding + user + menus, ETag-cached
  GET /api/v1/apps            → registered app inventory
  GET /healthz, /readyz       → ops probes

Auth:
  Keycloak Bearer JWT validated against the gosecCloud realm.
  Discovery URL is overridable so pods can hit Keycloak via the
  in-cluster service (https://keycloak.keycloak.svc.cluster.local:8443)
  while still validating the canonical issuer (auth.gosec.cloud).
  Lazy JWKS init — pod stays up if Keycloak is briefly unreachable.

Data model (gsc_core.shell):
  apps · menu_items (zone enum: topbar/sidebar/footer/user-menu) ·
  menu_role_grants (Keycloak realm roles, OR semantics, empty=all) ·
  branding

Seed includes the 8 gsc-crm sidebar items + topbar search +
user-menu (settings/support/logout) + footer (docs).

K8s:
  Namespace gsc-shell (ambient mesh).
  Deployment 2 replicas, internal-only ingress shell-api.gosec.internal,
  EJBCA SERVER cert.
  ServiceEntry for auth.gosec.cloud (vestigial — discovery now uses
  in-cluster path; keeping for ad-hoc curl from inside pods).
  Added to keycloak/allow-keycloak-clients AuthorizationPolicy out of band.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

k8s/deployment.yaml

@@ -0,0 +1,121 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: gsc-shell-api
+  namespace: gsc-shell
+  labels:
+    app.kubernetes.io/name: gsc-shell-api
+    app.kubernetes.io/component: api
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: gsc-shell-api
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: gsc-shell-api
+    spec:
+      containers:
+        - name: api
+          image: registry.gosec.internal/gsc-shell-api:v0.1.3
+          imagePullPolicy: IfNotPresent
+          ports:
+            - name: http
+              containerPort: 8080
+          env:
+            - name: PORT
+              value: "8080"
+            - name: KEYCLOAK_ISSUER
+              value: "https://auth.gosec.cloud/realms/gosecCloud"
+            # Discovery hits Keycloak via in-cluster service (pods can't reach
+            # public auth.gosec.cloud over TLS); the issuer claim still has
+            # to match the canonical hostname above.
+            - name: KEYCLOAK_DISCOVERY_URL
+              value: "https://keycloak.keycloak.svc.cluster.local:8443/realms/gosecCloud"
+            - name: CACHE_TTL_SECONDS
+              value: "60"
+            - name: DATABASE_URL
+              valueFrom:
+                secretKeyRef:
+                  name: gsc-shell-api-db
+                  key: database-url
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 8080
+            initialDelaySeconds: 5
+            periodSeconds: 30
+          readinessProbe:
+            httpGet:
+              path: /readyz
+              port: 8080
+            initialDelaySeconds: 3
+            periodSeconds: 10
+          resources:
+            requests:
+              cpu: 50m
+              memory: 64Mi
+            limits:
+              cpu: 250m
+              memory: 256Mi
+          securityContext:
+            runAsNonRoot: true
+            runAsUser: 1000
+            allowPrivilegeEscalation: false
+            readOnlyRootFilesystem: true
+            capabilities:
+              drop: [ALL]
+      imagePullSecrets:
+        - name: registry-credentials
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+            - weight: 100
+              podAffinityTerm:
+                labelSelector:
+                  matchLabels:
+                    app.kubernetes.io/name: gsc-shell-api
+                topologyKey: kubernetes.io/hostname
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: gsc-shell-api
+  namespace: gsc-shell
+  labels:
+    app.kubernetes.io/name: gsc-shell-api
+spec:
+  type: ClusterIP
+  selector:
+    app.kubernetes.io/name: gsc-shell-api
+  ports:
+    - name: http
+      port: 8080
+      targetPort: 8080
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: gsc-shell-api
+  namespace: gsc-shell
+  annotations:
+    nginx.ingress.kubernetes.io/ssl-redirect: "true"
+    nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
+spec:
+  ingressClassName: nginx
+  tls:
+    - hosts:
+        - shell-api.gosec.internal
+      secretName: gsc-shell-api-tls
+  rules:
+    - host: shell-api.gosec.internal
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: gsc-shell-api
+                port:
+                  number: 8080