Add Newton VBD tablecloth comparison

[maxkra15]

Description

Adds one focused Newton VBD tablecloth comparison implemented with Isaac Lab's direct-workflow APIs:

• scripts/demos/newton_tablecloth.py runs the classic trick at five pull speeds, arranged side by side in one scene.

The scene is declared with InteractiveSceneCfg, uses the default Isaac Lab ground plane, and follows the normal scene write/step/update lifecycle. SimReady kitchen-island and tableware assets provide the visuals, while measured analytic collision proxies keep rigid-soft contact inexpensive and robust. The tableware retains realistic masses; the contact and cloth discretization are tuned instead of making the props artificially heavy.

This remains a standalone demo because it is a deterministic side-by-side solver/contact comparison rather than a reusable agent task. The H1 manipulation workflow has intentionally been split out of this PR and converted into a registered manager-based task on a follow-up branch.

The demo defaults to the lightweight Newton GL viewer, supports the standard launcher visualizers, and uses Isaac Lab's existing video recorder with --video. No recorder API, bitrate override, or dependency is added.

Performance and solver updates

• Uses compliant ALM for VBD rigid contacts and joints.
• Colors active bending constraints before VBD graph capture while retaining the upstream optimization that disables the potentially unbounded color-balancing pass.
• Refreshes collision contacts every substep for fast, thin rigid-soft interactions.
• Uses full-surface rigid-soft contact and increases the existing per-body rigid-soft contact capacity for this contact-heavy scene.
• Leaves contact matching disabled because the scene does not use rigid contact history.
• Stores all five tableware sets in one RigidObjectCollection and keeps per-frame pull state GPU-resident.
• Forwards configured deformable color and opacity into Newton's cloth mesh so Newton GL and Kit render the authored appearance consistently.

The VBD public API addition is deliberately limited to rigid_compliant_alm, which this demo uses directly. Body-body contact capacity and AVBD stabilization remain owned by #7913; unused rigid-joint stiffness/damping fields were removed from this PR. Defaults and the compliant-ALM override are tested by constructing the real CPU SolverVBD, rather than only mocking argument forwarding.

Documentation

• Documents the demo and the relevant VBD solver/contact scheduling controls in the VBD tuning guide.
• Adds the required package changelog fragments and Isaac Lab test-only marker.

Type of change

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes VBD bending-constraint coloring and deformable appearance)

Validation

• Merged latest origin/develop (83df17e88).
• Completed the full five-table run on CUDA 0 without rendering (240 frames).
• 12 passed in the Newton VBD core tests, including real-solver default and compliant-ALM construction.
• 3 passed, 1 skipped, 434 deselected in the focused deformable/standalone contract checks; the skipped case requires a GUI.
• Full Sphinx current-docs build completed without warnings.
• uv run isaaclab -f passed all hooks with the changelog base set to develop.

Checklist

• I have read and understood the contribution guidelines.
• I have run the relevant formatting, lint, documentation, unit, and simulation checks.
• I registered the demo with standalone-script smoke coverage.
• I added the required changelog fragments.
• My name already exists in CONTRIBUTORS.md.

[kellyguo11]

do you want to land this on develop?