feat(pdf-tools): add attachments feature to embed files in PDFs

Implement new functionality to allow embedding attachments into PDF documents. The feature includes:
- UI for selecting PDF and files to attach
- Logic to embed files while preserving metadata
- Display of attached files with size information
- Download of modified PDF with embedded files

src/js/logic/linearize.ts

@@ -30,7 +30,9 @@ async function initializeQpdf() {
 
 export async function linearizePdf() {
   // Check if there are files and at least one PDF
-  const pdfFiles = state.files.filter((file: File) => file.type === 'application/pdf');
+  const pdfFiles = state.files.filter(
+    (file: File) => file.type === 'application/pdf'
+  );
   if (!pdfFiles || pdfFiles.length === 0) {
     showAlert('No PDF Files', 'Please upload at least one PDF file.');
     return;
@@ -43,12 +45,12 @@ export async function linearizePdf() {
   let errorCount = 0;
 
   try {
-    qpdf = await initializeQpdf(); 
+    qpdf = await initializeQpdf();
 
     for (let i = 0; i < pdfFiles.length; i++) {
       const file = pdfFiles[i];
-      const inputPath = `/input_${i}.pdf`; 
-      const outputPath = `/output_${i}.pdf`; 
+      const inputPath = `/input_${i}.pdf`;
+      const outputPath = `/output_${i}.pdf`;
 
       showLoader(`Optimizing ${file.name} (${i + 1}/${pdfFiles.length})...`);
 
@@ -58,23 +60,20 @@ export async function linearizePdf() {
 
         qpdf.FS.writeFile(inputPath, uint8Array);
 
-        const args = [
-          inputPath,
-          '--linearize',
-          outputPath,
-        ];
+        const args = [inputPath, '--linearize', outputPath];
 
         qpdf.callMain(args);
 
         const outputFile = qpdf.FS.readFile(outputPath, { encoding: 'binary' });
-         if (!outputFile || outputFile.length === 0) {
-             console.error(`Linearization resulted in an empty file for ${file.name}.`);
-             throw new Error(`Processing failed for ${file.name}.`);
-         }
+        if (!outputFile || outputFile.length === 0) {
+          console.error(
+            `Linearization resulted in an empty file for ${file.name}.`
+          );
+          throw new Error(`Processing failed for ${file.name}.`);
+        }
 
         zip.file(`linearized-${file.name}`, outputFile, { binary: true });
         successCount++;
-
       } catch (fileError: any) {
         errorCount++;
         console.error(`Failed to linearize ${file.name}:`, fileError);
@@ -91,13 +90,16 @@ export async function linearizePdf() {
             }
           }
         } catch (cleanupError) {
-          console.warn(`Failed to cleanup WASM FS for ${file.name}:`, cleanupError);
+          console.warn(
+            `Failed to cleanup WASM FS for ${file.name}:`,
+            cleanupError
+          );
         }
       }
-    } 
+    }
 
     if (successCount === 0) {
-       throw new Error('No PDF files could be linearized.');
+      throw new Error('No PDF files could be linearized.');
     }
 
     showLoader('Generating ZIP file...');
@@ -109,7 +111,6 @@ export async function linearizePdf() {
       alertMessage += ` ${errorCount} file(s) failed.`;
     }
     showAlert('Processing Complete', alertMessage);
-
   } catch (error: any) {
     console.error('Linearization process error:', error);
     showAlert(
@@ -119,4 +120,4 @@ export async function linearizePdf() {
   } finally {
     hideLoader();
   }
-}
+}