fix(pyproject): drop unresolvable vlabench extra

VLABench is not on PyPI — its only distribution is the
OpenMOSS/VLABench GitHub repo (package name `VLABench`, no PyPI
release) — so the `vlabench>=0.1.0` spec in the `[vlabench]` extra
was flatly unsatisfiable. Every `uv sync` (even with unrelated
extras like `--extra test`) validates the full lockfile graph and
tripped on this, breaking the fast-test CI step.

- Remove `vlabench = [...]` from pyproject.toml (left an explanatory
  comment in its place) and drop the `lerobot[vlabench]` entry from
  the `all` extra.
- Update docs/source/vlabench.mdx to document the manual
  `git clone` + editable install flow for VLABench, rrt-algorithms
  and the MuJoCo / dm_control pins — same pattern as robocasa.
- Docker image already does this via explicit git clones, so no CI
  image change is needed.

Made-with: Cursor

docs/source/vlabench.mdx

@@ -28,18 +28,18 @@ VLABench ships two task suites covering **43 task categories** in LeRobot's `--e
 
 ## Installation
 
-After following the standard LeRobot installation instructions:
+VLABench is **not on PyPI** — its only distribution is the [OpenMOSS/VLABench](https://github.com/OpenMOSS/VLABench) GitHub repo — so LeRobot does not expose a `vlabench` extra. Install it manually as an editable clone, alongside the MuJoCo / dm_control pins VLABench needs, then fetch the mesh assets:
 
 ```bash
-pip install -e ".[vlabench]"
-```
+# After following the standard LeRobot installation instructions.
 
-VLABench also ships simulation assets separately. Clone the repo and download them:
+git clone https://github.com/OpenMOSS/VLABench.git ~/VLABench
+git clone https://github.com/motion-planning/rrt-algorithms.git ~/rrt-algorithms
+pip install -e ~/VLABench -e ~/rrt-algorithms
+pip install "mujoco==3.2.2" "dm-control==1.0.22" \
+            open3d colorlog scikit-learn openai gdown
 
-```bash
-git clone https://github.com/OpenMOSS/VLABench.git
-cd VLABench
-python scripts/download_assets.py
+python ~/VLABench/scripts/download_assets.py
 ```
 
 <Tip>

pyproject.toml

@@ -206,7 +206,11 @@ aloha = ["lerobot[dataset]", "gym-aloha>=0.1.2,<0.2.0", "lerobot[scipy-dep]"]
 pusht = ["lerobot[dataset]", "gym-pusht>=0.1.5,<0.2.0", "pymunk>=6.6.0,<7.0.0"] # TODO: Fix pymunk version in gym-pusht instead
 libero = ["lerobot[dataset]", "lerobot[transformers-dep]", "hf-libero>=0.1.3,<0.2.0; sys_platform == 'linux'", "lerobot[scipy-dep]"]
 metaworld = ["lerobot[dataset]", "metaworld==3.0.0", "lerobot[scipy-dep]"]
-vlabench = ["lerobot[dataset]", "vlabench>=0.1.0; sys_platform == 'linux'", "mujoco==3.2.2", "dm-control==1.0.22", "lerobot[scipy-dep]"]
+# NOTE: vlabench is NOT exposed as a `lerobot` extra. Its only distribution
+# is the OpenMOSS/VLABench GitHub repo (package name `VLABench`, no PyPI
+# release), so any `vlabench>=X` pip spec is unresolvable. Install it
+# manually alongside MuJoCo / dm-control — see docs/source/vlabench.mdx
+# for the recipe.
 
 # All
 all = [
@@ -248,7 +252,6 @@ all = [
     "lerobot[phone]",
     "lerobot[libero]; sys_platform == 'linux'",
     "lerobot[metaworld]",
-    "lerobot[vlabench]; sys_platform == 'linux'",
     "lerobot[sarm]",
     "lerobot[peft]",
     # "lerobot[unitree_g1]", TODO: Unitree requires specific installation instructions for unitree_sdk2