line art (#5052)

## Summary
- introduce a shared line art conversion interface and proprietary
ImageMagick-backed implementation
- have the compress controller optionally autowire the enterprise
service before running per-image line art processing
- remove ImageMagick command details from core by delegating conversions
through the proprietary service

## Testing
- not run (not requested)


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[Codex
Task](https://chatgpt.com/codex/tasks/task_b_6928aecceaf083289a9269b1ca99307e)

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Co-authored-by: James Brunton <[email protected]>

frontend/src/core/hooks/tools/compress/useCompressOperation.ts

@@ -19,6 +19,11 @@ export const buildCompressFormData = (parameters: CompressParameters, file: File
   }
 
   formData.append("grayscale", parameters.grayscale.toString());
+  formData.append("lineArt", parameters.lineArt.toString());
+  if (parameters.lineArt) {
+    formData.append("lineArtThreshold", parameters.lineArtThreshold.toString());
+    formData.append("lineArtEdgeLevel", parameters.lineArtEdgeLevel.toString());
+  }
   return formData;
 };
 

frontend/src/core/hooks/tools/compress/useCompressParameters.ts

@@ -4,6 +4,9 @@ import { useBaseParameters, BaseParametersHook } from '@app/hooks/tools/shared/u
 export interface CompressParameters extends BaseParameters {
   compressionLevel: number;
   grayscale: boolean;
+  lineArt: boolean;
+  lineArtThreshold: number;
+  lineArtEdgeLevel: 1 | 2 | 3;
   expectedSize: string;
   compressionMethod: 'quality' | 'filesize';
   fileSizeValue: string;
@@ -13,6 +16,9 @@ export interface CompressParameters extends BaseParameters {
 export const defaultParameters: CompressParameters = {
   compressionLevel: 5,
   grayscale: false,
+  lineArt: false,
+  lineArtThreshold: 50,
+  lineArtEdgeLevel: 3,
   expectedSize: '',
   compressionMethod: 'quality',
   fileSizeValue: '',