Set email confirmation default to false

Change default behavior for email confirmation by initializing email_confirmation_required to 0 (not required) instead of 1. Remove the duplicate declaration and clarify the comment; existing logic still overrides this default (sets to 0 for matching pseudo_user/uuid_user and to 1 when event.requires_email_confirmation). Minor whitespace cleanup.

src/backend/src/routers/signup.js

@@ -260,9 +260,10 @@ module.exports = eggspress(['/signup'], {
         uuid_user = uuid_user[0];
     }
 
-    // email confirmation is required by default unless:
+    // email confirmation is not required by default
+    let email_confirmation_required = 0;
+
     // Pseudo user converting and matching uuid is provided
-    let email_confirmation_required = 1;
     if ( pseudo_user && uuid_user && pseudo_user.id === uuid_user.id )
     {
         email_confirmation_required = 0;