Harden core update loops and primitives

[S1mplector]

What changed

• bounded engine, tween, timeline, particle, and physics catch-up work after lag spikes
• made scene, tween, and physics callback mutations deterministic and exception-safe
• hardened camera, rigid-body, timing, and vector primitives against non-finite inputs and overflow
• reused physics broadphase buckets, pairs, bounds, and collision scratch state to reduce hot-path allocation
• added regression coverage for extreme deltas, callback mutation, stale cue catch-up, invalid numeric state, and particle caps

Why

Several core loops could perform unbounded work after a debugger pause or accept NaN/infinite values that poisoned subsequent frames. Scene and physics callbacks could also mutate live collections mid-traversal, producing skipped work or inconsistent state.

Impact

Runtime updates now remain bounded and structurally consistent under lag spikes, callback failures, and malformed numeric inputs, while common physics and geometry paths allocate less memory.

Validation

• ./gradlew :core:clean :core:test --tests 'com.jvn.core.tween.*' --tests 'com.jvn.core.physics.*' --tests 'com.jvn.core.engine.*' --tests 'com.jvn.core.math.*' --tests 'com.jvn.core.graphics.Camera2DTest' --tests 'com.jvn.core.animation.TimelineRunnerTest' --tests 'com.jvn.core.scene2d.*StabilityTest'
• git diff --check