feat(web): upgrade feature-flag-client to SSE streaming + getValue()

web/src/lib/feature-flags.ts

@@ -14,7 +14,12 @@ const client = createFeatureFlagClient({
   baseUrl: `${getBaseUrl()}/api`,
   productId: PRODUCT_ID,
   platform: 'web',
+  useStreaming: true,
   pollIntervalMs: 5 * 60 * 1000,
+  getAccessToken: () =>
+    typeof window !== 'undefined'
+      ? localStorage.getItem('access_token')
+      : null,
 });
 
 /**
@@ -35,6 +40,14 @@ export function getAllFlags(): Readonly<Record<string, boolean>> {
   return client.getAllFlags();
 }
 
+/** Get a multi-variate flag value. Returns defaultValue if not found. */
+export function getFeatureValue<T = boolean | string | number | Record<string, unknown>>(
+  key: string,
+  defaultValue: T,
+): T {
+  return client.getValue(key, defaultValue);
+}
+
 /** Stop polling and reset state. Useful for tests. */
 export function resetFeatureFlags(): void {
   client.stop();