Fix deprecated example API usage

[jcarius-nv]

Description

Follow-up to #3989. This PR must merge after #3989.

Migrate the five newly auto-discovered examples away from deprecated APIs and
remove their temporary strict-warning allowances. The examples now opt into
coordinate-layout joint targets where needed, the rigid-rigid VBD example uses
keyword arguments for add_shape_box(), and the RJ45 example no longer authors
the deprecated vbd:joint_is_hard attribute, which has no solver-mode effect
under its existing compliant ALM configuration.

This restores strict deprecation-warning enforcement for every auto-discovered
example.

GitHub's native stacked pull requests require all branches to live in the same
repository. Because #3989 is a cross-fork PR, this dependent PR temporarily
targets main and includes the parent changes in its comparison. The follow-up
change itself is commit a64ae9aa. After #3989 merges, this branch will be
rebased onto the updated main before this PR is marked ready.

Checklist

• New or existing tests cover these changes
• No documentation update is required for this API-use migration
• This maintenance-only change does not require a changelog fragment

Test plan

python -W error::DeprecationWarning -m newton.examples <each-offender> \
  --device cuda:0 --test --quiet --viewer null
# All five examples passed individually.

uv run --extra dev -m newton.tests -k TestAutoDiscoveredExamples \
  --strict-warnings --no-cache-clear
# 15 passed in 186.444s

uvx --python 3.12 pre-commit run -a
# passed

Before the migration, each of the five example commands failed with a
DeprecationWarning treated as an error.

Summary by CodeRabbit

• Improvements

  • Example test mode now consistently requires a test_final() validation step.
  • Automatically discovered examples receive baseline CUDA test coverage.
  • Several examples now support coordinate-layout targets and updated contact configurations.

• Bug Fixes

  • Improved loading-screen behavior during example initialization and execution.
  • Added clearer validation when an example lacks the required final test.

• Tests

  • Expanded coverage for example lifecycle behavior, automatic discovery, and viewer loading states.

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Run ID: 47f6d7e3-1e79-45f0-9945-5ac9a0f3b0f3

📥 Commits

Reviewing files that changed from the base of the PR and between 6ee9f02 and a64ae9a.

📒 Files selected for processing (10)

• docs/guide/development.rst
• newton/examples/__init__.py
• newton/examples/basic/example_basic_heightfield.py
• newton/examples/contacts/example_contacts_rj45_plug.py
• newton/examples/vbd/example_vbd_rigid_rigid_contact.py
• newton/examples/vbd/example_vbd_soft_rigid_contact.py
• newton/examples/vbd/example_vbd_soft_rigid_mix_contact.py
• newton/tests/test_example_runner.py
• newton/tests/test_examples.py
• newton/tests/test_viewer_loading_splash.py

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📝 Walkthrough

Walkthrough

The example runner now requires callable test_final() checks in test mode. Documentation describes automatic CUDA coverage for discovered examples. New lifecycle tests cover loading-splash behavior. Selected examples enable coordinate-layout targets and update VBD setup calls.

Changes

Example testing and initialization

Layer / File(s)	Summary
Runner finalization contract docs/guide/development.rst, newton/examples/__init__.py, newton/tests/test_example_runner.py, newton/tests/test_viewer_loading_splash.py	Test mode now validates callable test_final() before execution and calls it after the render loop. Lifecycle tests cover loading-splash behavior and the required error.
Automatic discovered-example coverage docs/guide/development.rst, newton/tests/test_examples.py	Documentation and tests define automatic CUDA null-viewer coverage for examples without explicit registrations.
Example initialization compatibility newton/examples/basic/example_basic_heightfield.py, newton/examples/contacts/example_contacts_rj45_plug.py, newton/examples/vbd/example_vbd_rigid_rigid_contact.py, newton/examples/vbd/example_vbd_soft_rigid_contact.py, newton/examples/vbd/example_vbd_soft_rigid_mix_contact.py	Selected examples enable coordinate-layout targets. The RJ45 plug example removes VBD custom attributes. Rigid contact shape calls use explicit keyword arguments.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to a64ae

This localized maintenance change removes deprecated example API usage and restores strict warning enforcement; no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: adenzler-nvidia

Sequence Diagram(s)

sequenceDiagram
  participant TestSuite
  participant newton.examples.init
  participant ViewerGL
  participant newton.examples.run
  participant Example
  TestSuite->>newton.examples.init: initialize example
  newton.examples.init->>ViewerGL: show loading splash for visible viewer
  TestSuite->>newton.examples.run: execute example
  newton.examples.run->>ViewerGL: hide loading splash
  newton.examples.run->>Example: call test_final() in test mode

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the primary change: migrating example code away from deprecated API usage.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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