Phase 4: SSO scaffolding, RBAC enforcement, tenant-scoped dashboards, audit logging, K8s deployment

RBAC (api/internal/authz) is live on /query and /dashboards, backed by a
new enterprise/ module (session issuance, audit logging, RBAC storage,
OIDC/SAML protocol wiring) that core never imports -- only calls over
HTTP. Found and fixed a real cross-tenant vulnerability in dashboards
(no tenant_id filtering at all) while writing the threat model doc.

Two things are explicitly NOT done, documented rather than hidden:
tenant isolation for log data itself (/query still shares one ClickHouse
connection and Tantivy index across every tenant -- RBAC controls who
can query, not what a query can see), and human SSO login (protocol
wiring exists, no HTTP handler calls it yet). See
docs/security/threat-model.md and docs/phase-4-runbook.md.

Also adds deploy/ (Go Operator + Helm chart, validated offline only --
no cluster was reachable in this environment).

deploy/helm/sentry/templates/web.yaml

@@ -0,0 +1,43 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: {{ .Release.Name }}-web
+  labels:
+    {{- include "sentry.labels" . | nindent 4 }}
+    {{- include "sentry.selectorLabels" (list $ "web") | nindent 4 }}
+spec:
+  replicas: {{ .Values.web.replicas }}
+  selector:
+    matchLabels:
+      {{- include "sentry.selectorLabels" (list $ "web") | nindent 6 }}
+  template:
+    metadata:
+      labels:
+        {{- include "sentry.selectorLabels" (list $ "web") | nindent 8 }}
+    spec:
+      containers:
+        - name: web
+          # No env vars here -- see values.yaml's web.builtWith* comment:
+          # this is a static build, its API base URLs are baked into the
+          # image, not configurable at the Deployment level.
+          image: "{{ .Values.web.image.repository }}:{{ .Values.web.image.tag }}"
+          imagePullPolicy: {{ .Values.global.imagePullPolicy }}
+          ports:
+            - name: http
+              containerPort: 3000
+          resources:
+            {{- toYaml .Values.web.resources | nindent 12 }}
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ .Release.Name }}-web
+  labels:
+    {{- include "sentry.labels" . | nindent 4 }}
+    {{- include "sentry.selectorLabels" (list $ "web") | nindent 4 }}
+spec:
+  selector:
+    {{- include "sentry.selectorLabels" (list $ "web") | nindent 4 }}
+  ports:
+    - name: http
+      port: 3000