OCR fix and Mobile QR changes (#5433)

# Description of Changes
## OCR / Tesseract path handling

Makes tessDataPath resolution deterministic with priority: config >
TESSDATA_PREFIX env > default.
Updates language discovery to use runtimePathConfig.getTessDataPath()
instead of raw config value.
Ensure default OCR dir is debian based not alpine

## Mobile scanner: feature gating + new conversion settings
Adds system.mobileScannerSettings (convert-to-PDF + resolution + page
format + stretch) exposed via backend config and configurable in the
proprietary admin UI.
Enforces enableMobileScanner on the MobileScannerController endpoints
(403 when disabled).
Frontend mobile upload flow can now optionally convert received images
to PDF (pdf-lib + canvas).

## Desktop/Tauri connectivity work
Expands tauri-plugin-http permissions and enables dangerous-settings.
Adds a very comprehensive multi-stage server connection diagnostic
routine (with lots of logging).


<img width="688" height="475" alt="image"
src="https://github.com/user-attachments/assets/6f9c1aec-58c7-449b-96b0-52f25430d741"
/>


---

## 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/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx

@@ -1,13 +1,14 @@
 import { useEffect } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useNavigate } from 'react-router-dom';
-import { Stack, Text, Loader, Group, Divider, Paper, Switch, Badge, Anchor } from '@mantine/core';
+import { Stack, Text, Loader, Group, Divider, Paper, Switch, Badge, Anchor, Select, Collapse } from '@mantine/core';
 import { alert } from '@app/components/toast';
 import LocalIcon from '@app/components/shared/LocalIcon';
 import RestartConfirmationModal from '@app/components/shared/config/RestartConfirmationModal';
 import { useRestartServer } from '@app/components/shared/config/useRestartServer';
 import { useAdminSettings } from '@app/hooks/useAdminSettings';
 import PendingBadge from '@app/components/shared/config/PendingBadge';
+import { Z_INDEX_CONFIG_MODAL } from '@app/styles/zIndex';
 import ProviderCard from '@app/components/shared/config/configSections/ProviderCard';
 import {
   ALL_PROVIDERS,
@@ -46,6 +47,10 @@ interface ConnectionsSettingsData {
   };
   ssoAutoLogin?: boolean;
   enableMobileScanner?: boolean;
+  mobileScannerConvertToPdf?: boolean;
+  mobileScannerImageResolution?: string;
+  mobileScannerPageFormat?: string;
+  mobileScannerStretchToFit?: boolean;
 }
 
 export default function AdminConnectionsSection() {
@@ -78,7 +83,11 @@ export default function AdminConnectionsSection() {
         saml2: securityData.saml2 || {},
         mail: mailData || {},
         ssoAutoLogin: premiumData.proFeatures?.ssoAutoLogin || false,
-        enableMobileScanner: systemData.enableMobileScanner || false
+        enableMobileScanner: systemData.enableMobileScanner || false,
+        mobileScannerConvertToPdf: systemData.mobileScannerSettings?.convertToPdf !== false,
+        mobileScannerImageResolution: systemData.mobileScannerSettings?.imageResolution || 'full',
+        mobileScannerPageFormat: systemData.mobileScannerSettings?.pageFormat || 'A4',
+        mobileScannerStretchToFit: systemData.mobileScannerSettings?.stretchToFit || false
       };
 
       // Merge pending blocks from all four endpoints
@@ -98,6 +107,18 @@ export default function AdminConnectionsSection() {
       if (systemData._pending?.enableMobileScanner !== undefined) {
         pendingBlock.enableMobileScanner = systemData._pending.enableMobileScanner;
       }
+      if (systemData._pending?.mobileScannerSettings?.convertToPdf !== undefined) {
+        pendingBlock.mobileScannerConvertToPdf = systemData._pending.mobileScannerSettings.convertToPdf;
+      }
+      if (systemData._pending?.mobileScannerSettings?.imageResolution !== undefined) {
+        pendingBlock.mobileScannerImageResolution = systemData._pending.mobileScannerSettings.imageResolution;
+      }
+      if (systemData._pending?.mobileScannerSettings?.pageFormat !== undefined) {
+        pendingBlock.mobileScannerPageFormat = systemData._pending.mobileScannerSettings.pageFormat;
+      }
+      if (systemData._pending?.mobileScannerSettings?.stretchToFit !== undefined) {
+        pendingBlock.mobileScannerStretchToFit = systemData._pending.mobileScannerSettings.stretchToFit;
+      }
 
       if (Object.keys(pendingBlock).length > 0) {
         result._pending = pendingBlock;
@@ -356,6 +377,35 @@ export default function AdminConnectionsSection() {
 
       const response = await apiClient.put('/api/v1/admin/settings', { settings: deltaSettings });
 
+      if (response.status === 200) {
+        alert({
+          alertType: 'success',
+          title: t('admin.settings.success', 'Settings saved successfully')
+        });
+        fetchSettings();
+      }
+    } catch (error) {
+      console.error('Failed to save mobile scanner setting:', error);
+      alert({
+        alertType: 'error',
+        title: t('admin.settings.error', 'Failed to save settings')
+      });
+    }
+  };
+
+  const handleMobileScannerSettingsSave = async (settingKey: string, newValue: string | boolean) => {
+    // Block save if login is disabled or mobile scanner is not enabled
+    if (!validateLoginEnabled() || !settings?.enableMobileScanner) {
+      return;
+    }
+
+    try {
+      const deltaSettings = {
+        [`system.mobileScannerSettings.${settingKey}`]: newValue
+      };
+
+      const response = await apiClient.put('/api/v1/admin/settings', { settings: deltaSettings });
+
       if (response.status === 200) {
         alert({
           alertType: 'success',
@@ -471,6 +521,119 @@ export default function AdminConnectionsSection() {
               <PendingBadge show={isFieldPending('enableMobileScanner')} />
             </Group>
           </div>
+
+          {/* Mobile Scanner Settings - Only show when enabled */}
+          <Collapse in={settings?.enableMobileScanner || false}>
+            <Stack gap="md" mt="md" ml="lg" style={{ borderLeft: '2px solid var(--mantine-color-gray-3)', paddingLeft: '1rem' }}>
+              {/* Convert to PDF */}
+              <div>
+                <Text size="sm" fw={500} mb="xs">
+                  {t('admin.settings.connections.mobileScannerConvertToPdf', 'Convert Images to PDF')}
+                </Text>
+                <Text size="xs" c="dimmed" mb="sm">
+                  {t('admin.settings.connections.mobileScannerConvertToPdfDesc', 'Automatically convert uploaded images to PDF format. If disabled, images will be kept as-is.')}
+                </Text>
+                <Group gap="xs">
+                  <Switch
+                    checked={settings?.mobileScannerConvertToPdf !== false}
+                    onChange={(e) => {
+                      if (!loginEnabled) return;
+                      const newValue = e.target.checked;
+                      setSettings({ ...settings, mobileScannerConvertToPdf: newValue });
+                      handleMobileScannerSettingsSave('convertToPdf', newValue);
+                    }}
+                    disabled={!loginEnabled}
+                  />
+                  <PendingBadge show={isFieldPending('mobileScannerConvertToPdf')} />
+                </Group>
+              </div>
+
+              {/* PDF Conversion Settings - Only show when convertToPdf is enabled */}
+              {settings?.mobileScannerConvertToPdf !== false && (
+                <>
+                  {/* Image Resolution */}
+                  <div>
+                    <Text size="sm" fw={500} mb="xs">
+                      {t('admin.settings.connections.mobileScannerImageResolution', 'Image Resolution')}
+                    </Text>
+                    <Text size="xs" c="dimmed" mb="sm">
+                      {t('admin.settings.connections.mobileScannerImageResolutionDesc', 'Resolution of uploaded images. "Reduced" scales images to max 1200px to reduce file size.')}
+                    </Text>
+                    <Group gap="xs">
+                      <Select
+                        value={settings?.mobileScannerImageResolution || 'full'}
+                        onChange={(value) => {
+                          if (!loginEnabled) return;
+                          setSettings({ ...settings, mobileScannerImageResolution: value || 'full' });
+                          handleMobileScannerSettingsSave('imageResolution', value || 'full');
+                        }}
+                        data={[
+                          { value: 'full', label: t('admin.settings.connections.imageResolutionFull', 'Full (Original Size)') },
+                          { value: 'reduced', label: t('admin.settings.connections.imageResolutionReduced', 'Reduced (Max 1200px)') }
+                        ]}
+                        disabled={!loginEnabled}
+                        style={{ width: '250px' }}
+                        comboboxProps={{ zIndex: Z_INDEX_CONFIG_MODAL }}
+                      />
+                      <PendingBadge show={isFieldPending('mobileScannerImageResolution')} />
+                    </Group>
+                  </div>
+
+                  {/* Page Format */}
+                  <div>
+                    <Text size="sm" fw={500} mb="xs">
+                      {t('admin.settings.connections.mobileScannerPageFormat', 'Page Format')}
+                    </Text>
+                    <Text size="xs" c="dimmed" mb="sm">
+                      {t('admin.settings.connections.mobileScannerPageFormatDesc', 'PDF page size for converted images. "Keep" uses original image dimensions.')}
+                    </Text>
+                    <Group gap="xs">
+                      <Select
+                        value={settings?.mobileScannerPageFormat || 'A4'}
+                        onChange={(value) => {
+                          if (!loginEnabled) return;
+                          setSettings({ ...settings, mobileScannerPageFormat: value || 'A4' });
+                          handleMobileScannerSettingsSave('pageFormat', value || 'A4');
+                        }}
+                        data={[
+                          { value: 'keep', label: t('admin.settings.connections.pageFormatKeep', 'Keep (Original Dimensions)') },
+                          { value: 'A4', label: t('admin.settings.connections.pageFormatA4', 'A4 (210×297mm)') },
+                          { value: 'letter', label: t('admin.settings.connections.pageFormatLetter', 'Letter (8.5×11in)') }
+                        ]}
+                        disabled={!loginEnabled}
+                        style={{ width: '250px' }}
+                        comboboxProps={{ zIndex: Z_INDEX_CONFIG_MODAL }}
+                      />
+                      <PendingBadge show={isFieldPending('mobileScannerPageFormat')} />
+                    </Group>
+                  </div>
+
+                  {/* Stretch to Fit */}
+                  <div>
+                    <Text size="sm" fw={500} mb="xs">
+                      {t('admin.settings.connections.mobileScannerStretchToFit', 'Stretch to Fit')}
+                    </Text>
+                    <Text size="xs" c="dimmed" mb="sm">
+                      {t('admin.settings.connections.mobileScannerStretchToFitDesc', 'Stretch images to fill the entire page. If disabled, images are centered with preserved aspect ratio.')}
+                    </Text>
+                    <Group gap="xs">
+                      <Switch
+                        checked={settings?.mobileScannerStretchToFit || false}
+                        onChange={(e) => {
+                          if (!loginEnabled) return;
+                          const newValue = e.target.checked;
+                          setSettings({ ...settings, mobileScannerStretchToFit: newValue });
+                          handleMobileScannerSettingsSave('stretchToFit', newValue);
+                        }}
+                        disabled={!loginEnabled}
+                      />
+                      <PendingBadge show={isFieldPending('mobileScannerStretchToFit')} />
+                    </Group>
+                  </div>
+                </>
+              )}
+            </Stack>
+          </Collapse>
         </Stack>
       </Paper>