fix(admin): secure proxied model mutations

frontend/src/modules/identity/host.ts

@@ -9,7 +9,7 @@ export interface IdentityAuthHandlers {
   POST: IdentityRequestHandler;
 }
 
-function normalizeHost(value: string | null): string | null {
+export function normalizeIdentityHost(value: string | null): string | null {
   if (!value || value !== value.trim() || /[\s,@/\\]/.test(value)) return null;
 
   try {
@@ -33,7 +33,7 @@ export function resolveIdentitySurface(
   hostHeader: string | null,
   config: SelfHostedIdentityConfig,
 ): "user" | "admin" | null {
-  const host = normalizeHost(hostHeader);
+  const host = normalizeIdentityHost(hostHeader);
   if (!host) return null;
 
   if (host === new URL(config.userOrigin).host.toLowerCase()) return "user";