feat: support secure XFT submission attachments

test/distribution.test.ts

@@ -103,8 +103,8 @@ test("customer distribution prefers remote MCP OAuth and keeps a generic compati
   assert.match(localDrafts, /Never store[\s\S]*templateId[\s\S]*confirmationId[\s\S]*complete upstream schema/);
   assert.match(localDrafts, /outcome_uncertain[\s\S]*freeze[\s\S]*Never prepare or submit it again automatically/);
   assert.match(localDrafts, /never on the approval gateway/);
-  assert.match(localDrafts, /local attachment path.*never a valid upstream attachment field value.*native client/s);
-  assert.match(createApproval, /Local file paths.*not valid attachment field values.*native client/s);
+  assert.match(localDrafts, /localPath.*signed Bridge.*does not upload.*final confirmation.*native-client completion/s);
+  assert.match(createApproval, /Local file paths.*not valid `values` or `customFieldValues`.*signed Bridge `attachments`.*submit uploads only after final confirmation.*native client/s);
   assert.match(createApproval, /every XFT selection.*label-only.*optionSource.*returned `label` values.*`code` only inside/s);
   assert.match(createApproval, /Never show, explain, or ask.*city code.*organization code.*employee number.*numeric cabin value.*`expenseNumber`.*`expTypeCode`/s);
   assert.match(createApproval, /selectionCapability\.status=client_only.*required field stops.*optional field may be skipped/s);