feat(training): add VLA pi0 AzureML training

[junkataoka]

Problem

training/vla/scripts/ and training/vla/workflows/ are empty. There is no AzureML path to train pi0 / pi0_fast policies on the toolchain, despite LeRobot upstream supporting them via --policy.type=pi0.

Proposed solution

Add a pi0 AzureML training submit script + workflow YAML, forked from the IL LeRobot training submission. Key constraint: do not vendor the OpenPI fork. LeRobot / HuggingFace already support pi0 upstream — passing --policy.type=pi0 to lerobot-train is sufficient.

Acceptance criteria

• training/vla/scripts/submit-azureml-vla-training.sh submits a pi0 training CommandJob
• training/vla/workflows/azureml/vla-training.yaml defines the job
• No OpenPI fork code vendored
• README documents pi0 / pi0_fast usage

Related

• PR: feat(training): add VLA pi0 AzureML training stack #916 (draft)