fix(site): use domain email in public metadata

Co-Authored-By: First Fluke <our.first.fluke@gmail.com>

Author: gahyun-git

lib/site.ts

@@ -3,7 +3,7 @@ export const SITE = {
   legalName: "퍼스트플루크 (FIRST FLUKE)",
   url: "https://firstfluke.com",
   threadsHandle: "mega_fluke",
-  contactEmail: "our.first.fluke@gmail.com",
+  contactEmail: "hello@firstfluke.com",
   selectionPageUrl: "https://www.modoo.or.kr/ai-solution/organization/841",
   selectionLabel: "모두의 창업 2026 선정",
 } as const;