fix: integrate PR #3396 review feedback (round 2)

- envs(vlabench): drop the unused `episode_index` / `n_envs`
  constructor args — they were stored but never referenced.
- envs(vlabench): replace module-level `print()` calls with the
  standard `logging.getLogger(__name__)` logger (matches the rest
  of the repo's script convention). Covers the two PhysicsError
  retry/step paths and the `create_vlabench_envs` progress lines.
- envs(vlabench): drop `_make_env_fns` and build factories
  MetaWorld-style via a lambda list comprehension — simpler, no
  extra helper.
- docker(vlabench): pin upstream clones to commit SHAs
  (`OpenMOSS/VLABench@cf588fe6`, `motion-planning/rrt-algorithms@e51d95ee`)
  so benchmark images are reproducible.
- ci(vlabench): run `scripts/ci/extract_task_descriptions.py` after
  the eval so `metrics.json` carries per-task natural-language
  labels, matching LIBERO / MetaWorld jobs. Added a VLABench
  extractor that produces cleaned-name labels keyed by `<task>_0`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/ci/extract_task_descriptions.py

@@ -57,6 +57,21 @@ def _metaworld_descriptions(task_name: str) -> dict[str, str]:
     return {f"{task_name}_0": label}
 
 
+def _vlabench_descriptions(task_spec: str) -> dict[str, str]:
+    """For each task in the comma-separated list, emit a cleaned-name label.
+
+    VLABench tasks carry language instructions on their dm_control task
+    object, but pulling them requires loading the full env per task
+    (~seconds each). The CI smoke-eval already captures the instruction
+    inside its episode info; this mapping is just enough to key
+    `metrics.json` by `<task>_0`.
+    """
+    out: dict[str, str] = {}
+    for task in (t.strip() for t in task_spec.split(",") if t.strip()):
+        out[f"{task}_0"] = task.replace("_", " ").strip()
+    return out
+
+
 def main() -> int:
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument("--env", required=True, help="Environment family (libero, metaworld, ...)")
@@ -70,6 +85,8 @@ def main() -> int:
             descriptions = _libero_descriptions(args.task)
         elif args.env == "metaworld":
             descriptions = _metaworld_descriptions(args.task)
+        elif args.env == "vlabench":
+            descriptions = _vlabench_descriptions(args.task)
         else:
             print(
                 f"[extract_task_descriptions] No description extractor for env '{args.env}'.",