Add support for add_feature in lerobot_edit_dataset.py

[vovw]

What this does

Adds add_feature operation to the lerobot_edit_dataset script, allowing users to add
new features to existing datasets from numpy files.

How it was tested

• Added handle_add_feature function in src/lerobot/scripts/lerobot_edit_dataset.py
• Implemented feature loading from .npy files with validation for:
  • Data length matching dataset total frames
  • Required metadata (dtype, shape, names)
  • File existence checks
• Integrated with existing add_features utility from dataset_tools
• Added documentation and usage example in docstring

Create a sample feature file

python -c "import numpy as np; np.save('rewards.npy', np.random.randn(1000,1).astype('float32'))"

Add feature to dataset

python -m lerobot.scripts.lerobot_edit_dataset \
    --repo_id lerobot/pusht \
    --operation.type add_feature \
    --operation.features '{"reward": {"file": "rewards.npy", "dtype": "float32", "shape": [1], "names": null}}'

resolves one of the #2326

[Copilot]

Pull Request Overview

Adds support for a new add_feature operation to the lerobot_edit_dataset.py script, enabling users to add new features to existing datasets by loading data from numpy files.

• Implements handle_add_feature function with validation for data length, metadata, and file existence
• Adds AddFeatureConfig dataclass for configuration
• Updates documentation with usage examples

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

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[vovw]

@jadechoghari ? wdyt