Huge bunch of UI/UX improvements and tweaks!

server/api/admin/pre-registrants/invite.post.js

@@ -26,8 +26,8 @@ export default defineEventHandler(async (event) => {
   const results = []
 
   for (const preReg of preRegs) {
-    // Only send to selected pre-registrants (skip already invited/accepted/expired)
-    if (preReg.status !== 'selected' && preReg.status !== 'pending') {
+    // Only send to pending/selected/invited (allow resend); skip accepted/expired
+    if (preReg.status !== 'selected' && preReg.status !== 'pending' && preReg.status !== 'invited') {
       results.push({
         preRegistrantId: preReg._id,
         email: preReg.email,