feat(rewards): add Robometer reward model

[philipmit]

Title

Added Robometer, a popular new reward model (Robometer website and arXiv paper)

Type / Scope

• Type: Feature
• Scope: rewards / robometer

Summary / Motivation

This PR adds the popular new reward model, Robometer, under the new reward-model foundation in src/lerobot/rewards/.

This is in line with the call for contributions from #3143.

Implementation is aligned with the Robometer paper: arXiv:2603.02115.

This PR follows a similar structure as the PR for adding RoboReward (another new reward model) submitted by int-smart.

Related issues

• Reward Models: call for contributions #3143

What changed

• Added new Robometer module files:
  • src/lerobot/rewards/robometer/configuration_robometer.py
  • src/lerobot/rewards/robometer/modeling_robometer.py
  • src/lerobot/rewards/robometer/__init__.py
• Registered Robometer in reward registry/factory:
  • src/lerobot/robometer/__init__.py
  • src/lerobot/robometer/factory.py
• Added tests:
  • tests/rewards/test_robometer.py
• Added docs:
  • docs/source/robometer.mdx

How was this tested (or how to run locally)

• Tests added: tests/rewards/test_robometer.py

Example:

• Ran the relevant tests:

  pytest tests/rewards/test_robometer.py -v

Checklist (required before merge)

• Linting/formatting run (pre-commit run -a)
• All tests pass locally (pytest)
• Documentation updated
• CI is green

Example videos (successful and failed)

Task: "Pick up the cube and place it in the target area marked by the X."

jackvial_so101_pickplace_recap_merged_v2_episode_0.mp4

jackvial_so101_pickplace_recap_merged_v2_episode_14.mp4