fix(form-validate): context-aware Check 12 — ExternalDataProcessorObject is error in config

Detect config vs EPF context by walking up from FormPath looking for
Configuration.xml. ExternalDataProcessorObject/ExternalReportObject are
valid in EPF/ERF but cause XDTO exception in configuration context.

- EPF forms: no warning (ExternalDataProcessorObject is correct)
- Config forms: ERROR with hint to use DataProcessorObject/ReportObject
- Fix test DSLs: compiled-form, table-form used wrong External* type

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

tests/skills/cases/form-validate/table-form.json

@@ -21,7 +21,7 @@
           ]}
         ],
         "attributes": [
-          { "name": "Объект", "type": "ExternalDataProcessorObject.ВалТабл", "main": true },
+          { "name": "Объект", "type": "DataProcessorObject.ВалТабл", "main": true },
           { "name": "Данные", "type": "ValueTable", "columns": [
             { "name": "Наименование", "type": "string(150)" },
             { "name": "Количество", "type": "decimal(10,3)" }