Freeze batch-aware Frontier ablation

runs/frontier-fidelity-envelope-v1/run_frontier_qwen30_exact_trace_surface.py

@@ -148,6 +148,14 @@ def find_request_metrics(run_dir: Path) -> Path:
     return matches[0]
 
 
+def trace_manifest_entry(trace: dict[str, Any]) -> dict[str, Any]:
+    return {
+        key: str(value) if isinstance(value, Path) else value
+        for key, value in trace.items()
+        if key != "shapes"
+    }
+
+
 def score(path: Path, expected_shapes: list[tuple[int, int]]) -> dict[str, Any]:
     with path.open(newline="") as source:
         rows = list(csv.DictReader(source))
@@ -409,10 +417,7 @@ def main() -> None:
             "allreduce_csv": str(args.allreduce_csv) if args.allreduce_csv else None,
             "allreduce_csv_sha256": BASE.sha256(args.allreduce_csv) if args.allreduce_csv else None,
         },
-        "traces": [
-            {key: value for key, value in trace.items() if key != "shapes"}
-            for trace in traces
-        ],
+        "traces": [trace_manifest_entry(trace) for trace in traces],
         "config_results": config_results,
         "rankings": rankings,
     }