Submit gate: accept unparseable candidates (eval scores them invalid/0)

A present-but-unloadable output.step (empty, or parses to no geometry) was
rejecting the entire submission. The evaluator's CAD-validity gate already
scores any non-valid solid as cad_score=0 (status=invalid), so a bad candidate
is a legitimate zero-scoring outcome, not a submission error. The gate now logs
and lets it through instead of blocking the whole zip.

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

submit.py

@@ -716,22 +716,32 @@ def _validate_candidates_parseable(unpacked: Path, fixture_names: set[str]) -> N
             # Missing output is a valid benchmark outcome: the evaluator writes
             # status="missing" and the fixture contributes cad_score=0.
             return
+        # A present-but-unloadable candidate is NOT a submission error. The
+        # evaluator's CAD-validity gate scores any non-valid solid as
+        # cad_score=0 (status="invalid"), so an empty or unparseable file is a
+        # legitimate (zero-scoring) outcome, not a reason to reject the whole
+        # submission. We only log here; the gate never blocks on candidate
+        # content, so one bad part can't sink an otherwise-valid submission.
         if candidate.stat().st_size == 0:
-            raise _ValidationError(
-                f"Sample `{name}` has an empty `{candidate.name}`."
+            logger.warning(
+                "Sample %s has an empty %s; will score 0 (invalid).",
+                name, candidate.name,
             )
+            return
         suffix = candidate.suffix.lower()
         if suffix in {".step", ".stp"}:
             try:
                 parse_step(candidate)
-            except RuntimeError as e:
-                raise _ValidationError(
-                    f"Sample `{name}` has an `{candidate.name}` that is not "
-                    f"loadable as STEP geometry: {e}"
-                ) from e
+            except Exception as e:  # noqa: BLE001 - non-fatal; eval scores it 0
+                logger.warning(
+                    "Sample %s has an %s that is not loadable as STEP (%s); "
+                    "will score 0 (invalid).",
+                    name, candidate.name, e,
+                )
         else:  # pragma: no cover - _candidate_path constrains suffixes
-            raise _ValidationError(
-                f"Sample `{name}` uses unsupported candidate file `{candidate.name}`."
+            logger.warning(
+                "Sample %s uses unexpected candidate file %s; will score 0.",
+                name, candidate.name,
             )
 
     with ThreadPoolExecutor(