perf: add database indexes, implement caching, enforce permission guards, and sanitize external URLs

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

@@ -21,6 +21,7 @@ export class EmailController {
   ) {}
 
   @Get()
+  @RequirePermissions(Permission.VIEW_MAIL)
   async getEmails(
     @Query('status') status?: string,
     @Query('limit') limit?: string,
@@ -38,6 +39,7 @@ export class EmailController {
   }
 
   @Get(':id')
+  @RequirePermissions(Permission.VIEW_MAIL)
   async getEmail(@Param('id') id: string) {
     return this.emailRepo.findOneOrFail({
       where: { Id: parseInt(id, 10) },
@@ -46,6 +48,7 @@ export class EmailController {
   }
 
   @Get(':id/attachments')
+  @RequirePermissions(Permission.VIEW_MAIL)
   async getAttachments(@Param('id') id: string) {
     return this.attachmentRepo.find({
       where: { EmailMessageId: parseInt(id, 10) },
@@ -54,6 +57,7 @@ export class EmailController {
   }
 
   @Get('attachments/:attachmentId/content')
+  @RequirePermissions(Permission.VIEW_MAIL)
   async getAttachmentContent(
     @Param('attachmentId') attachmentId: string,
     @Res() res: Response,