translations and login page (#5008)

# Description of Changes

<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

frontend/public/locales/en-GB/translation.json

@@ -3517,6 +3517,8 @@
     "accountCreatedSuccess": "Account created successfully! You can now sign in.",
     "passwordChangedSuccess": "Password changed successfully! Please sign in with your new password.",
     "credentialsUpdated": "Your credentials have been updated. Please sign in again.",
+    "defaultCredentials": "Default Login Credentials",
+    "changePasswordWarning": "Please change your password after logging in for the first time",
     "slides": {
       "overview": {
         "alt": "Stirling PDF overview",

frontend/src/proprietary/routes/Login.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useState } from 'react';
 import { useNavigate, useSearchParams } from 'react-router-dom';
+import { Text, Stack, Alert } from '@mantine/core';
 import { springAuth } from '@app/auth/springAuthClient';
 import { useAuth } from '@app/auth/UseSession';
 import { useTranslation } from 'react-i18next';
@@ -29,6 +30,8 @@ export default function Login() {
   const [enabledProviders, setEnabledProviders] = useState<string[]>([]);
   const [hasSSOProviders, setHasSSOProviders] = useState(false);
   const [_enableLogin, setEnableLogin] = useState<boolean | null>(null);
+  const [isFirstTimeSetup, setIsFirstTimeSetup] = useState(false);
+  const [showDefaultCredentials, setShowDefaultCredentials] = useState(false);
 
   // Redirect immediately if user has valid session (JWT already validated by AuthProvider)
   useEffect(() => {
@@ -55,6 +58,10 @@ export default function Login() {
 
           setEnableLogin(data.enableLogin ?? true);
 
+          // Set first-time setup flags
+          setIsFirstTimeSetup(data.firstTimeSetup ?? false);
+          setShowDefaultCredentials(data.showDefaultCredentials ?? false);
+
           // Extract provider IDs from the providerList map
           // The keys are like "/oauth2/authorization/google" - extract the last part
           const providerIds = Object.keys(data.providerList || {})
@@ -259,6 +266,31 @@ export default function Login() {
         </div>
       )}
 
+      {/* Help section - only show on first-time setup with default credentials */}
+      {isFirstTimeSetup && showDefaultCredentials && (
+        <Alert
+          color="blue"
+          variant="light"
+          radius="md"
+          mt="xl"
+        >
+          <Stack gap="xs" align="center">
+            <Text size="sm" fw={600} ta="center">
+              {t('login.defaultCredentials', 'Default Login Credentials')}
+            </Text>
+            <Text size="sm" ta="center">
+              <Text component="span" fw={600}>{t('login.username', 'Username')}:</Text> admin
+            </Text>
+            <Text size="sm" ta="center">
+              <Text component="span" fw={600}>{t('login.password', 'Password')}:</Text> stirling
+            </Text>
+            <Text size="xs" c="dimmed" ta="center" mt="xs">
+              {t('login.changePasswordWarning', 'Please change your password after logging in for the first time')}
+            </Text>
+          </Stack>
+        </Alert>
+      )}
+
     </AuthLayout>
   );
 }