Godot/Rapier 2D rollback query-coherence repro with two-peer CI

[clark719664]

Sharing an AI-assisted, reproducible Godot/Rapier 2D reference for rollback users investigating stale collision queries. It uses the original bomb-game fixture's DeltaRollback driver; it is not a Netfox integration. Netfox's rollback caveats describe the same class of physics-query timing problem.

The fixture restores moving StaticBody2D child hitboxes, synchronizes them before the regular Rapier step, and runs blast queries afterward. Canonical hashing preserves dictionary values and types while ordering keys.

Preview release and reproduction instructions · CI evidence

CI exercises two real ENet peers with 100 ms ±20 ms artificial delay on both pinned Rapier versions. All 240 confirmed states/hashes match across peers and the zero-delay reference; an independent collision oracle catches the baseline and injected faults, with zero mismatches for the fix.

Scope: this static-hitbox fixture only. Dynamic bodies, CharacterBody caches, Area signals and cross-platform determinism are unverified. Feedback on the reproduction and its limits is welcome.