feat(perception): stabilize pre-capture methodology

src/k1link/compute/e30_materialization.py

@@ -254,7 +254,7 @@ def build_e30_materialization(
             source=source,
         )
 
-        identity = {
+        identity: dict[str, object] = {
             "schema_version": E30_MATERIALIZATION_SCHEMA,
             "review_pack": {
                 "result_id": _required_string(review.manifest, "result_id"),
@@ -635,7 +635,14 @@ def _engineering_triage(
 ) -> dict[str, object]:
     """Route evidence without pretending that a rule is a semantic verdict."""
 
-    selected_count = int(metadata["selected_point_count"])
+    selected_count_value = metadata["selected_point_count"]
+    if (
+        not isinstance(selected_count_value, int)
+        or isinstance(selected_count_value, bool)
+        or selected_count_value < 0
+    ):
+        raise E30MaterializationError("selected point count is invalid")
+    selected_count = selected_count_value
     detector_score = metadata.get("detector_score")
     stratum = _required_string(item, "stratum")
     locator = _required_object(item, "e29_locator")