feat: implement segment-based PDF download functionality with a dedicated UI for multi-page export

paperless-backend/src/inbox/inbox.controller.ts

@@ -176,14 +176,15 @@ export class InboxController {
     await this.inboxService.updateSource(id, body.source, preferredUsername);
   }
 
-  @Get(':id/download')
-  async download(
+  @Post(':id/download-segment')
+  async downloadSegment(
     @Param('id') id: string,
+    @Body() body: { pages: number[] },
     @Request() req: any,
     @Res({ passthrough: true }) res: Response,
   ): Promise<StreamableFile> {
     const preferredUsername: string | null = req.user?.preferredUsername ?? null;
-    const { buffer, filename } = await this.inboxService.getEditedPdfBuffer(id, preferredUsername);
+    const { buffer, filename } = await this.inboxService.getSegmentPdfBuffer(id, preferredUsername, body.pages ?? []);
     const { Readable } = await import('stream');
     res.setHeader('Content-Type', 'application/pdf');
     res.setHeader('Content-Disposition', `attachment; filename="${encodeURIComponent(filename)}"`);