Core: Improve engine stability, fix lifecycle logging, and increase test coverage

[GuilhermeF03]

Summary

This PR focuses on hardening the core engine stability and significantly expanding the unit test suite to improve long-term reliability. It addresses critical timing issues in the physics loop, fixes lifecycle logging bugs, and introduces automated coverage reporting.

Changes

Core Engine & Lifecycle

• SceneManager: Implemented a robust while-loop physics accumulator with a MAX_PHYSICS_STEPS safety cap (8 steps). This prevents physics desync during frame rate drops and protects against the "spiral of death."
• • SceneManager: Persisted viewportWidth and viewportHeight state to allow late-registering systems to query dimensions immediately after setup.
• • App Lifecycle: Refactored the shutdown sequence to execute onExit hooks before tearing down the logging subsystem, ensuring final cleanup logs are correctly captured.
• • Node Observability: Added TRACE level logging for path resolution to provide visibility when the engine transparently skips wrapper nodes.

Build & Infrastructure

• Kotlin Upgrade: Upgraded Kotlin version to 2.3.20.
• • Kover Reports: Enabled automated HTML and XML Kover coverage report generation on the check task.

Test Suite & Quality

• Test Expansion: Added 29 new test files across engine, adapters, and tooling modules.
• • Refactoring: Renamed EmptyNode to TestNode project-wide to clarify the distinction between internal engine components and test doubles.
• • Coverage: Verified 146 passing tests with instruction coverage reports now integrated into the build process.

How to Test

1. Run the full test suite and verify all 146 tests pass:
2. ./gradlew test
3. 2. Generate and inspect the coverage report:
4. ./gradlew check
5. 3. Verify that physics timing remains consistent even under simulated lag in SceneManagerTests.

[DanielSousa01]

🤖

[GuilhermeF03]

Closed, was a simple test of Antigravity and Codex - will be used for more atomic tasks. This PR also fails the contribution guidelines