fix(form-validate): add ExternalDataProcessorObject/ExternalReportObject to valid cfg prefixes

Check 12 was flagging cfg:ExternalDataProcessorObject.X as "unrecognized cfg
prefix", but this is a valid XDTO type for external data processor (EPF) forms.
Found via snapshot verification against epf-add-form snapshots.

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

.claude/skills/form-validate/scripts/form-validate.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# form-validate v1.2 — Validate 1C managed form
+# form-validate v1.3 — Validate 1C managed form
 # Source: https://github.com/Nikolay-Shirokov/cc-1c-skills
 
 import argparse
@@ -43,6 +43,7 @@ VALID_CFG_PREFIXES = {
     'ChartOfCharacteristicTypesObject', 'ChartOfCharacteristicTypesRef',
     'ConstantsSet', 'DataProcessorObject', 'DocumentObject', 'DocumentRef',
     'DynamicList', 'EnumRef', 'ExchangePlanObject', 'ExchangePlanRef',
+    'ExternalDataProcessorObject', 'ExternalReportObject',
     'InformationRegisterRecordManager', 'InformationRegisterRecordSet',
     'ReportObject', 'TaskObject', 'TaskRef',
 }
@@ -103,6 +104,18 @@ def main():
 
     root = tree.getroot()
 
+    # Detect context: config vs EPF/ERF
+    is_config_context = False
+    walk_dir = os.path.dirname(os.path.abspath(form_path))
+    for _ in range(15):
+        parent = os.path.dirname(walk_dir)
+        if parent == walk_dir:
+            break
+        if os.path.isfile(os.path.join(walk_dir, 'Configuration.xml')):
+            is_config_context = True
+            break
+        walk_dir = parent
+
     errors = 0
     warnings = 0
     ok_count = 0
@@ -645,7 +658,10 @@ def main():
                 suffix = tv[4:]  # after "cfg:"
                 prefix = suffix.split(".")[0]
                 if prefix in VALID_CFG_PREFIXES or suffix == "DynamicList":
-                    pass  # OK
+                    # ExternalDataProcessorObject/ExternalReportObject valid only in EPF/ERF context
+                    if is_config_context and prefix in ('ExternalDataProcessorObject', 'ExternalReportObject'):
+                        report_warn(f'12. Type "{tv}": External* type in configuration context (use DataProcessorObject/ReportObject instead)')
+                        type_warn_count += 1
                 else:
                     report_warn(f'12. Type "{tv}": unrecognized cfg prefix')
                     type_warn_count += 1