Fix run_eval.py: resolve output-dir to absolute path

When --output-dir is relative and fabro runs from /tmp, generated
workflow.toml paths were unresolvable.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

evals/swe-bench/run_eval.py

@@ -314,6 +314,7 @@ def main():
     )
     args = parser.parse_args()
 
+    args.output_dir = args.output_dir.resolve()
     args.output_dir.mkdir(parents=True, exist_ok=True)
     setup_logging(args.output_dir)