[V2] feat(convert): add support for CBZ to PDF and PDF to CBZ conversion (#4831)

# Description of Changes


TLDR:
- Implemented `ConvertFromCbzSettings` component for CBZ to PDF options
- Added `ConvertToCbzSettings` component for PDF to CBZ options
- Extended conversion constants with new CBZ-related formats and
mappings
- Updated `ConvertSettings` to include CBZ-specific configuration forms
- Updated `useConvertOperation` to handle CBZ conversion parameters

For backend reference see this PR: #4472

This pull request adds support for converting between CBZ (Comic Book
Zip) and PDF formats in the frontend conversion tool. It introduces new
UI components for CBZ-to-PDF and PDF-to-CBZ conversion options, updates
the conversion parameters and form data logic, and integrates these
formats into the available conversion options and endpoints.

**CBZ/PDF Conversion Support:**

* Added `ConvertFromCbzSettings` and `ConvertToCbzSettings` components
to provide user options for CBZ-to-PDF and PDF-to-CBZ conversions,
including "Optimize for ebook" and DPI settings.

**Conversion Logic and Parameters:**

* Extended the `ConvertParameters` interface and default parameters to
include `cbzOptions` (for CBZ-to-PDF) and `cbzOutputOptions` (for
PDF-to-CBZ).

**Conversion Matrix and Endpoint Integration:**

* Added CBZ to the supported "from" and "to" format lists, updated the
conversion matrix to allow CBZ-to-PDF and PDF-to-CBZ, and mapped the new
conversions to appropriate API endpoints.
* Updated URL mapping to recognize `/cbz-to-pdf` and `/pdf-to-cbz` as
conversion tool routes.

### Front-end

<img width="1852" height="994" alt="image"
src="https://github.com/user-attachments/assets/b902438a-8ce7-4eed-a4f8-d80677c0c796"
/>
<img width="270" height="994" alt="image"
src="https://github.com/user-attachments/assets/87556380-e0c5-4974-93c2-d36f86268b49"
/>
<img width="417" height="389" alt="image"
src="https://github.com/user-attachments/assets/1889a3ec-0c06-442a-b3bb-71e1a7c34e4c"
/>
<img width="1853" height="994" alt="image"
src="https://github.com/user-attachments/assets/d6d68f5f-ed70-4be9-89b1-2e4b7cd90921"
/>
<img width="265" height="994" alt="image"
src="https://github.com/user-attachments/assets/36a05dd5-164f-46a7-b8af-aa815d6c0767"
/>




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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

- [X] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [X] 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)
- [X] I have performed a self-review of my own code
- [X] 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)

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

### Testing (if applicable)

- [X] 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.

---------

Signed-off-by: Balázs Szücs <[email protected]>

frontend/src/core/components/fileEditor/FileEditorThumbnail.tsx

@@ -93,6 +93,13 @@ const FileEditorThumbnail = ({
     return (m?.[1] || '').toUpperCase();
   }, [file.name]);
 
+  const extLower = useMemo(() => {
+    const m = /\.([a-z0-9]+)$/i.exec(file.name ?? '');
+    return (m?.[1] || '').toLowerCase();
+  }, [file.name]);
+
+  const isCBZ = extLower === 'cbz';
+
   const pageLabel = useMemo(
     () =>
       pageCount > 0
@@ -206,7 +213,7 @@ const FileEditorThumbnail = ({
           alert({ alertType: 'success', title: `Unzipping ${file.name}`, expandable: false, durationMs: 2500 });
         }
       },
-      hidden: !isZipFile || !onUnzipFile,
+      hidden: !isZipFile || !onUnzipFile || isCBZ,
     },
     {
       id: 'close',

frontend/src/core/components/tools/convert/ConvertFromCbzSettings.tsx

@@ -0,0 +1,36 @@
+import { Stack, Text, Checkbox } from '@mantine/core';
+import { useTranslation } from 'react-i18next';
+import { ConvertParameters } from '@app/hooks/tools/convert/useConvertParameters';
+
+interface ConvertFromCbzSettingsProps {
+  parameters: ConvertParameters;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const ConvertFromCbzSettings = ({
+  parameters,
+  onParameterChange,
+  disabled = false
+}: ConvertFromCbzSettingsProps) => {
+  const { t } = useTranslation();
+
+  return (
+    <Stack gap="sm" data-testid="cbz-settings">
+      <Text size="sm" fw={500}>{t('convert.cbzOptions', 'CBZ to PDF Options')}:</Text>
+
+      <Checkbox
+        label={t('convert.optimizeForEbook', 'Optimize PDF for ebook readers (uses Ghostscript)')}
+        checked={parameters.cbzOptions.optimizeForEbook}
+        onChange={(event) => onParameterChange('cbzOptions', {
+          ...parameters.cbzOptions,
+          optimizeForEbook: event.currentTarget.checked
+        })}
+        disabled={disabled}
+        data-testid="optimize-ebook-checkbox"
+      />
+    </Stack>
+  );
+};
+
+export default ConvertFromCbzSettings;

frontend/src/core/components/tools/convert/ConvertSettings.tsx

@@ -13,6 +13,8 @@ import ConvertToImageSettings from "@app/components/tools/convert/ConvertToImage
 import ConvertFromImageSettings from "@app/components/tools/convert/ConvertFromImageSettings";
 import ConvertFromWebSettings from "@app/components/tools/convert/ConvertFromWebSettings";
 import ConvertFromEmailSettings from "@app/components/tools/convert/ConvertFromEmailSettings";
+import ConvertFromCbzSettings from "@app/components/tools/convert/ConvertFromCbzSettings";
+import ConvertToCbzSettings from "@app/components/tools/convert/ConvertToCbzSettings";
 import ConvertToPdfaSettings from "@app/components/tools/convert/ConvertToPdfaSettings";
 import { ConvertParameters } from "@app/hooks/tools/convert/useConvertParameters";
 import {
@@ -118,6 +120,12 @@ const ConvertSettings = ({
     onParameterChange('pdfaOptions', {
       outputFormat: 'pdfa-1',
     });
+    onParameterChange('cbzOptions', {
+      optimizeForEbook: false,
+    });
+    onParameterChange('cbzOutputOptions', {
+      dpi: 150,
+    });
     onParameterChange('isSmartDetection', false);
     onParameterChange('smartDetectionType', 'none');
   };
@@ -180,6 +188,12 @@ const ConvertSettings = ({
     onParameterChange('pdfaOptions', {
       outputFormat: 'pdfa-1',
     });
+    onParameterChange('cbzOptions', {
+      optimizeForEbook: false,
+    });
+    onParameterChange('cbzOutputOptions', {
+      dpi: 150,
+    });
   };
 
 
@@ -293,6 +307,30 @@ const ConvertSettings = ({
         </>
       )}
 
+      {/* CBZ to PDF options */}
+      {parameters.fromExtension === 'cbz' && parameters.toExtension === 'pdf' && (
+        <>
+          <Divider />
+          <ConvertFromCbzSettings
+            parameters={parameters}
+            onParameterChange={onParameterChange}
+            disabled={disabled}
+          />
+        </>
+      )}
+
+      {/* PDF to CBZ options */}
+      {parameters.fromExtension === 'pdf' && parameters.toExtension === 'cbz' && (
+        <>
+          <Divider />
+          <ConvertToCbzSettings
+            parameters={parameters}
+            onParameterChange={onParameterChange}
+            disabled={disabled}
+          />
+        </>
+      )}
+
       {/* PDF to PDF/A options */}
       {parameters.fromExtension === 'pdf' && parameters.toExtension === 'pdfa' && (
         <>

frontend/src/core/components/tools/convert/ConvertToCbzSettings.tsx

@@ -0,0 +1,39 @@
+import { Stack, Text, NumberInput } from '@mantine/core';
+import { useTranslation } from 'react-i18next';
+import { ConvertParameters } from '@app/hooks/tools/convert/useConvertParameters';
+
+interface ConvertToCbzSettingsProps {
+  parameters: ConvertParameters;
+  onParameterChange: <K extends keyof ConvertParameters>(key: K, value: ConvertParameters[K]) => void;
+  disabled?: boolean;
+}
+
+const ConvertToCbzSettings = ({
+  parameters,
+  onParameterChange,
+  disabled = false
+}: ConvertToCbzSettingsProps) => {
+  const { t } = useTranslation();
+
+  return (
+    <Stack gap="sm" data-testid="cbz-output-settings">
+      <Text size="sm" fw={500}>{t('convert.cbzOutputOptions', 'PDF to CBZ Options')}:</Text>
+
+      <NumberInput
+        data-testid="cbz-dpi-input"
+        label={t('convert.cbzDpi', 'DPI for image rendering')}
+        value={parameters.cbzOutputOptions.dpi}
+        onChange={(val) => typeof val === 'number' && onParameterChange('cbzOutputOptions', {
+          ...parameters.cbzOutputOptions,
+          dpi: val
+        })}
+        min={72}
+        max={600}
+        step={1}
+        disabled={disabled}
+      />
+    </Stack>
+  );
+};
+
+export default ConvertToCbzSettings;