Add Railiance staged-promotion overlay for flex-auth

FLEX-WP-0011 T01/T02: railiance.app.v1 contract, independently pinned
Helm values for tenant-engine and user-engine, isolated canary cycle
(deploy/observe/promote/rollback), and emergency kubectl path retained.
T03 waits on the custodian drain-plan row.

charts/flex-auth/templates/deployment.yaml

@@ -0,0 +1,48 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: {{ include "flex-auth.name" . }}
+  labels:
+    {{- include "flex-auth.labels" . | nindent 4 }}
+spec:
+  replicas: {{ .Values.replicaCount }}
+  selector:
+    matchLabels:
+      {{- include "flex-auth.selectorLabels" . | nindent 6 }}
+  template:
+    metadata:
+      labels:
+        {{- include "flex-auth.labels" . | nindent 8 }}
+    spec:
+      automountServiceAccountToken: false
+      securityContext:
+        runAsNonRoot: true
+        seccompProfile:
+          type: RuntimeDefault
+      containers:
+        - name: flex-auth
+          image: {{ include "flex-auth.image" . }}
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
+          args:
+            {{- toYaml .Values.args | nindent 12 }}
+          ports:
+            - name: http
+              containerPort: {{ .Values.service.port }}
+          livenessProbe:
+            httpGet:
+              path: {{ .Values.health.path }}
+              port: http
+            periodSeconds: 20
+          readinessProbe:
+            httpGet:
+              path: {{ .Values.health.path }}
+              port: http
+            periodSeconds: 5
+          resources:
+            {{- toYaml .Values.resources | nindent 12 }}
+          securityContext:
+            allowPrivilegeEscalation: false
+            capabilities:
+              drop:
+                - ALL
+            readOnlyRootFilesystem: true