Prepare pipelines before source execution

docs/policy/architecture.md

@@ -90,6 +90,12 @@ and verifies module availability and capabilities before execution. Structural
 pipeline choices must not be scattered through conditionals or hidden behind
 ad hoc command flags.
 
+Resolution validates every selected module and validator option set. A separate
+preparation boundary then constructs the complete input, chunk, lane,
+validation, and output implementation set in pipeline order. The runner accepts
+only that prepared set, so construction and dependency failures occur before
+source parsing or any other module operation.
+
 Stage ownership is explicit:
 
 - input modules convert external material into the generic source model;