Enable G1 SDG hand contact sensors

[jaybdub]

Description

Enables contact reporting on the G1 robot spawn configuration used by the locomanipulation SDG environment. This allows the left and right hand contact sensors to resolve their bodies during environment initialization.

Tracks NVBug 6682681.

Type of change

• Bug fix

Validation

• Reproduced the reported ContactSensor initialization failure from release/3.0.0 in headless Isaac Sim 6.0.1.
• Verified the fixed environment initializes both hand sensors and returns force tensors.
• uv run --no-sync python tools/changelog/cli.py check develop
• uv run isaaclab -f

Screenshots

Not applicable.

Checklist

• I have read and understood the contribution guidelines.
• I have run the pre-commit checks.
• No documentation change is required for this configuration fix.
• My changes generate no new warnings.
• I have run a fail-before/pass-after simulator regression check.
• I have added an isaaclab_mimic changelog fragment.
• The contributor already appears in repository revision history.

[isaaclab-review-bot]

Isaac Lab Review Bot

The PR locally enables contact reporting for the G1 locomanipulation SDG robot spawn and adds the required isaaclab_mimic changelog fragment. The change directly addresses initialization of the inherited hand contact sensors without broadening the patch.

• Design and architecture: The fix is scoped to G1LocomanipulationSDGEnvCfg.post_init, where this configuration defines its own initialization behavior. This is a small, targeted correction rather than a broader change to shared robot or environment configuration.
• API: No public symbols or constructor signatures change. The effective spawn configuration now enables contact sensors for this environment, which is the intended behavioral correction, and the user-visible fix is documented in a package changelog fragment.
• Implementation: The new assignment sets self.scene.robot.spawn.activate_contact_sensors before the remaining simulation, controller, and termination configuration. Nothing later in the shown initialization path overwrites the flag, so it remains enabled when the configured robot is spawned.

No blocking issues. No inline issue met the actionable-evidence threshold; the assessment above records the review feedback.

Automated review; human maintainers own approval decisions.

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge; the configuration change uses the established mechanism required by the inherited hand contact sensors.

Summary

• Enables contact reporting on the G1 robot spawn configuration.
• Adds an isaaclab_mimic changelog fragment documenting the fix.

[rwiltz]

@jaybdub do we want to cherry pick this to release/3.0.0?