Add CYD browser flasher with Next.js, i18n, and Web Serial install.

Replace the starter app with a public/local flasher that discovers sibling firmwares, supports en/zh, and documents HTTPS deploy.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -30,8 +30,14 @@ yarn-debug.log*
 yarn-error.log*
 .pnpm-debug.log*
 
-# env files (can opt-in for committing if needed)
-.env*
+# env files
+.env
+.env.local
+.env.*.local
+!.env.example
+
+# mirrored firmwares (run npm run sync:firmware for public deploy)
+/firmware/
 
 # vercel
 .vercel