account system、custom prompt

web/src/lib/config.ts

@@ -0,0 +1,27 @@
+export interface SystemConfig {
+  admin_mode: boolean;
+}
+
+let configPromise: Promise<SystemConfig> | null = null;
+let cachedConfig: SystemConfig | null = null;
+
+export function getSystemConfig(): Promise<SystemConfig> {
+  if (cachedConfig) {
+    return Promise.resolve(cachedConfig);
+  }
+  if (configPromise) {
+    return configPromise;
+  }
+  configPromise = fetch('/api/config')
+    .then((res) => res.json())
+    .then((data: SystemConfig) => {
+      cachedConfig = data;
+      return data;
+    })
+    .finally(() => {
+      // Keep cachedConfig for reuse; allow re-fetch via explicit invalidation if added later
+    });
+  return configPromise;
+}
+
+