Add PCB intra-pair skew only when the datasheet gives millimetres.

PS-SI-001 and decoupling skip without a numeric layout_rule. Tests use simple_project nets, not invented USBPHY boards.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/pinscopex/eval_report.py

@@ -31,6 +31,7 @@ from backend.pinscopex.lifecycle import check_lifecycle
 from backend.pinscopex.errata_check import check_errata
 from backend.pinscopex.internal_features_check import check_internal_features
 from backend.pinscopex.placement_check import check_placement
+from backend.pinscopex.si_check import check_si
 
 
 class EvalScores(BaseModel):
@@ -101,6 +102,7 @@ def run_deterministic_on_graph(graph: DesignGraph) -> list[Finding]:
     out.extend(check_errata(graph, cmap))
     out.extend(check_internal_features(graph, cmap))
     out.extend(check_placement(graph, cmap, None))
+    out.extend(check_si(graph, cmap, None))
     return out