feat: add six rigid labware checkpoint environments

[Steafy7]

Summary

Adds dedicated one-environment-per-asset Matterix checkpoint environments for
the six Batch 1 labware payloads:

• Corning 4980-50 and 4980-250 flasks
• DURAN 218012458 (100 mL) and 218014459 (500 mL) capped bottles
• Falcon 352096 (15 mL) and 352070 (50 mL) capped tubes

The capped checkpoints preserve the authored two-body fixed-joint USD payloads
by spawning them as generic USD scene assets rather than routing them through
Isaac Lab's single-rigid-body RigidObject loader. The Matterix_assets data
submodule points to the six-payload branch from the companion asset PR.

The workflow launcher also gains the controls required by the visual-review
runbook: WebRTC launcher argument forwarding, unique --record_path support,
and --episodes 1 termination for a finite review run. The Isaac Sim 5.1
render-setting compatibility change is limited to removing the obsolete
fractional-cutout setting.

Validation actually passed

On this clean PR branch, with the six-payload asset submodule commit checked
out:

• Python syntax compilation passed for all new configs, helpers, task modules,
  the registry, and scripts/run_workflow.py.
• Matterix-Test-Rigid-Labware-Flask-50-Franka-v1 /
  pick_and_place_flask_50: headless, one episode, unique record path — PASS.
• Matterix-Test-Rigid-Labware-Flask-250-Franka-v1 /
  pick_and_place_flask_250: headless, one episode, unique record path — PASS.
• Matterix-Test-Rigid-Labware-Duran-100-Franka-v1 /
  pick_and_place_duran_100: headless, one episode, unique record path — PASS.
• Matterix-Test-Rigid-Labware-Duran-500-Franka-v1 /
  pick_and_place_duran_500: headless, one episode, unique record path — PASS.
• Matterix-Test-Rigid-Labware-Falcon-15-Franka-v1 /
  pick_and_place_falcon_15: headless, one episode, unique record path — PASS.
• Matterix-Test-Rigid-Labware-Falcon-50-Franka-v1 /
  pick_and_place_falcon_50: headless, one episode, unique record path — PASS.
• Manual WebRTC GUI review: user confirmed all six visual checkpoints looked
  good.

This is a draft PR for review alongside AccelerationConsortium/Matterix_assets PR #14.