chore: streaming spike (#8907)

We need this PR to correctly set up CORS for streaming-related endpoints
in our spike and add the flag to our types.

---------

Co-authored-by: kwasniew <kwasniewski.mateusz@gmail.com>

src/lib/app.ts

@@ -112,6 +112,10 @@ export default async function getApp(
         `${baseUriPath}/api/frontend*`,
         corsOriginMiddleware(services, config),
     );
+    app.options(
+        `${baseUriPath}/api/streaming*`,
+        corsOriginMiddleware(services, config),
+    );
 
     app.use(baseUriPath, patMiddleware(config, services));
 

src/lib/types/experimental.ts

@@ -59,7 +59,8 @@ export type IFlagKey =
     | 'showUserDeviceCount'
     | 'deleteStaleUserSessions'
     | 'memorizeStats'
-    | 'licensedUsers';
+    | 'licensedUsers'
+    | 'streaming';
 
 export type IFlags = Partial<{ [key in IFlagKey]: boolean | Variant }>;
 
@@ -279,6 +280,10 @@ const flags: IFlags = {
         process.env.UNLEASH_EXPERIMENTAL_FLAG_LICENSED_USERS,
         false,
     ),
+    streaming: parseEnvVarBoolean(
+        process.env.UNLEASH_EXPERIMENTAL_STREAMING,
+        false,
+    ),
 };
 
 export const defaultExperimentalOptions: IExperimentalOptions = {