feat: move email sending into background jobs for retry support

Each direct mailer.sendMail() call is replaced by a dedicated background
job so that email delivery failures can be retried independently.

New jobs: send-pending-email, send-completed-email, send-forgot-password-email,
send-document-super-delete-email, send-recipient-removed-email,
send-document-deleted-emails, send-2fa-token-email, send-resend-document-email,
send-direct-template-created-email.

Existing handlers (send-document-cancelled-emails, send-organisation-member-*,
send-recipient-signed-email) have io.runTask wrappers removed since they
interfere with the job scheduler. Job triggers are dispatched after
transactions commit to avoid race conditions with uncommitted data.

packages/trpc/server/admin-router/delete-document.ts

@@ -1,5 +1,4 @@
 import { adminSuperDeleteDocument } from '@documenso/lib/server-only/admin/admin-super-delete-document';
-import { sendDeleteEmail } from '@documenso/lib/server-only/document/send-delete-email';
 
 import { adminProcedure } from '../trpc';
 import {
@@ -19,10 +18,9 @@ export const deleteDocumentRoute = adminProcedure
       },
     });
 
-    await sendDeleteEmail({ envelopeId: id, reason });
-
     await adminSuperDeleteDocument({
       envelopeId: id,
+      reason,
       requestMetadata: ctx.metadata.requestMetadata,
     });
   });