submit: dump full eval/report subprocess output to container log on failure

submit.py

@@ -688,7 +688,14 @@ def _run_eval(run_dir: Path) -> None:
         check=False,
     )
     if proc.returncode != 0:
-        # Surface a short tail of stderr; full output is in Space logs above.
+        # Dump the full subprocess output to the container log so the
+        # actual child crash (segfault, OSMesa init error, etc.) is
+        # recoverable via the Space's run logs. The user-facing
+        # failure_reason field stays short (200 chars cap downstream).
+        logger.error(
+            "cadgenbench evaluate exited %s\n--- STDERR ---\n%s\n--- STDOUT ---\n%s",
+            proc.returncode, proc.stderr or "", proc.stdout or "",
+        )
         tail = (proc.stderr or proc.stdout or "")[-500:].strip()
         raise RuntimeError(
             f"cadgenbench evaluate exited {proc.returncode}: {tail}"
@@ -711,6 +718,10 @@ def _run_report(run_dir: Path, html_out: Path) -> None:
         check=False,
     )
     if proc.returncode != 0 or not html_out.is_file():
+        logger.error(
+            "cadgenbench report single exited %s\n--- STDERR ---\n%s\n--- STDOUT ---\n%s",
+            proc.returncode, proc.stderr or "", proc.stdout or "",
+        )
         tail = (proc.stderr or proc.stdout or "")[-500:].strip()
         raise RuntimeError(
             f"cadgenbench report single exited {proc.returncode}: {tail}"