Add type-safe artifact lane resolution

internal/framework/contracts/contracts_test.go

@@ -12,10 +12,10 @@ import (
 
 var _ InputAdapter = fakeAdapter{}
 var _ Chunker = fakeChunker{}
-var _ Extractor = fakeExtractor{}
-var _ Merger = fakeMerger{}
-var _ Normalizer = fakeNormalizer{}
-var _ Validator = fakeValidator{}
+var _ LegacyRawExtractor = fakeExtractor{}
+var _ LegacyRawMerger = fakeMerger{}
+var _ LegacyRawNormalizer = fakeNormalizer{}
+var _ LegacyRawValidator = fakeValidator{}
 var _ StructuredLLMClient = fakeLLMClient{}
 var _ OutputEncoder = fakeOutputEncoder{}