fix: add missing CE error allowlist for custom widget and REST integration tests

The TestMxCheck_DoctypeScripts integration test fails because:
- 17-custom-widget-examples.mdl has known CE0463 (TEXTFILTER template
  mismatch) and CE1613 (ComboBox enum as association) but no allowlist entry
- 06-rest-client-examples.mdl gained SEND REST REQUEST microflows that
  may produce CE6035 (unsupported error handling)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

mdl/executor/roundtrip_doctype_test.go

@@ -29,12 +29,17 @@ var scriptModuleDeps = map[string][]string{
 var scriptKnownCEErrors = map[string][]string{
 	"06-rest-client-examples.mdl": {
 		"CE0061", // No entity selected (JSON response/body mapping without entity)
+		"CE6035", // RestOperationCallAction error handling not supported
 		"CE7056", // Undefined parameter (dynamic header {1} placeholder)
 		"CE7062", // Missing Accept header
 		"CE7064", // POST/PUT must include body
 		"CE7073", // Constant needs to be defined (auth with $ConstantName)
 		"CE7247", // Name cannot be empty (body mapping without entity)
 	},
+	"17-custom-widget-examples.mdl": {
+		"CE0463", // Widget definition changed (TEXTFILTER template property count mismatch)
+		"CE1613", // ComboBox enum attribute written as association pointer
+	},
 }
 
 // TestMxCheck_DoctypeScripts executes each doctype-tests/*.mdl example script