Address review comments about error message

Author: rmunn

frontend/src/lib/components/Users/CreateUser.svelte

@@ -27,7 +27,7 @@
     name: z.string().trim().min(1, $t('register.name_missing')),
     email: z.string().trim()
       .min(1, $t('project_page.add_user.empty_user_field'))
-      .refine((value) => isEmail(value) || (allowUsernames && usernameRe.test(value)), { message: $t('register.invalid_input') }),
+      .refine((value) => isEmail(value) || (allowUsernames && usernameRe.test(value)), (value) => ({ message: isEmail(value) ? $t('register.invalid_email', { email: value }) : $t('register.invalid_username', {username: value}) })),
     password: passwordFormRules($t),
     score: z.number(),
     locale: z.string().trim().min(2).default(userLocale),
@@ -43,7 +43,7 @@
         $errors.email = [$t('register.account_exists')];
       }
       if (error.invalidInput) {
-        $errors.email = [$t('register.invalid_input')];
+        $errors.email = [$t('register.invalid_input', { username: $form.email })];
       }
       return;
     }

frontend/src/lib/i18n/locales/en.json

@@ -225,7 +225,7 @@ the [Linguistics Institute at Payap University](https://li.payap.ac.th/) in Chia
       "shared_password_description": "For new users",
       "usernames": "Logins or emails (one per line)",
       "usernames_description": "This will be the **Send/Receive login** for new users",
-      "invalid_username": "Invalid login/username: {username}. Can only use letters, numbers, and underscore (_) characters.",
+      "invalid_username": "Invalid login/username: {username}. Only letters, numbers, and underscore (_) characters are allowed.",
       "empty_user_field": "Please enter email addresses and/or logins",
       "creator_must_have_email": "You must have an email address in order to create a project.",
       "members_added": "{addedCount} new {addedCount, plural, one {member was} other {members were}} added to project.",
@@ -389,7 +389,9 @@ If you don't see a dialog or already closed it, click the button below:",
   "register": {
     "title": "Register",
     "account_exists": "An account with this email already exists",
-    "invalid_input": "Please specify an email address or a valid username",
+    "invalid_email": "Invalid email address: {email}",
+    "invalid_username": "Invalid login/username: {username}. Only letters, numbers, and underscore (_) characters are allowed.",
+    "invalid_input": "Invalid email address or login/username: {username}. Only letters, numbers, and underscore (_) characters are allowed.",
     "button_register": "Register",
     "label_email": "Email",
     "label_email_or_username": "Email or login/username",