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).

cli/cmd/sentryctl/main.go

@@ -73,7 +73,13 @@ Commands:
 
 --api defaults to $SENTRYCTL_API_URL, or `+defaultAPIURL+` if unset.
 --alerting-api defaults to $SENTRYCTL_ALERTING_API_URL, or `+defaultAlertingURL+` if unset.
---language overrides auto-detection; omit it for the common case.`)
+--language overrides auto-detection; omit it for the common case.
+
+$SENTRYCTL_TOKEN, if set, is sent as "Authorization: Bearer <token>" on
+every request -- required once a deployment configures enterprise-auth
+(see /docs/phase-4-rbac-design.md). No flag equivalent, deliberately:
+unlike --api, a credential shouldn't be typed where shell history or
+`+"`ps`"+` output can capture it.`)
 }
 
 func resolveAPIURL(env func(string) string) string {
@@ -90,6 +96,14 @@ func resolveAlertingURL(env func(string) string) string {
 	return defaultAlertingURL
 }
 
+// resolveToken reads the RoleService/human bearer credential sentryctl
+// presents to api/alerting once enterprise-auth enforcement is turned
+// on (api/internal/authz.RequireRole*) -- empty by default, matching
+// every other Phase 0-3 client's nil-authorizer no-op behavior.
+func resolveToken(env func(string) string) string {
+	return env("SENTRYCTL_TOKEN")
+}
+
 type errorResponseBody struct {
 	Error string `json:"error"`
 }