feat: add generic review projection and reporting

tests/test_models.py

@@ -146,3 +146,9 @@ def test_transform_result_enforces_status_specific_output_fields() -> None:
             current_sha256=snapshot.sha256,
             partial_markdown=snapshot.markdown,
         )
+
+
+def test_error_stage_distinguishes_preflight_from_modifier_execution() -> None:
+    assert ErrorStage.PREFLIGHT.value == "preflight"
+    assert ErrorStage.TRANSFORM.value == "transform"
+    assert ErrorStage.FINAL_REVIEW.value == "final_review"