test: cover share authentication and copy behavior

lib/share/session.ts

@@ -0,0 +1,17 @@
+import { ShareHttpError } from "@/lib/share/http-error";
+
+export type ShareSession = {
+  user?: {
+    id?: string | null;
+    discordId?: string | null;
+  } | null;
+} | null;
+
+export function requireShareSessionIdentity(session: ShareSession) {
+  const userId = session?.user?.id;
+  const discordId = session?.user?.discordId;
+  if (!userId || !discordId) {
+    throw new ShareHttpError("Unauthorized", 401);
+  }
+  return { userId, discordId };
+}