Fix RT resource lifetimes and shader payload UB

[ComfyFluffy]

Summary

• replace frame-age lifetime assumptions with exact graphics-timeline completion tokens
• use one opaque GraphicsUse / TrackedGraphicsUse model for publication, reusable rings, and retirement
• retire terrain, light-grid, entity, and overlay scratch resources through the GPU executor's deferred-destruction queue
• fix the ray-tracing payload ABI mismatch and keep shadow traversal state local
• keep shader RNG samples strictly in [0, 1)

Lifetime model

• RtComposite reserves one graphics-use token before recording RT work and signals it after the world-overlay command buffer, the frame's final TLAS consumer
• asynchronously published terrain and light-grid builds retain their build-timeline dependency until the next graphics frame attaches it
• reusable TLAS, entity, push-data, and descriptor-set slots wait for their exact prior use before mutation, then mark the current token
• entity frame lists, geometry tables, persistent BLAS slots, rigid-reuse owners, and block-entity caches track their exact last use
• replaced or evicted published resources retire through the shared graphics-timeline queue; never-published build results use the unpublished retirement path
• render-thread assertions guard token reservation, marking, waiting, and tracked-owner retirement

Ring depths (4 or 6) are now latency/capacity choices rather than correctness horizons.

Shader fixes

• use the common Payload structure in raygen, any-hit, and miss stages reachable by the trace
• replace module-static shadow visibility state with a local, fully initialized shadow payload
• return explicit VisibilityResult { transmittance, waterHitT } values from shadow traversal
• derive random floats from the exactly representable high 24 bits so conversion cannot round to 1.0

Simplification

• remove frame-count deferred-release lists from terrain/entity/overlay paths covered by the graphics timeline
• batch overlay scratch destruction once per frame
• share completed-timeline snapshots across related reuse checks
• remove redundant TLAS ring-slot/use plumbing and stale frame-horizon comments

Non-goals

• DLSS feature release and persistent pipeline/output recreation keep their existing device-idle synchronization because their consumers are not all represented by the RT graphics token
• this does not add RtBuffer generation poisoning or raw-handle use-after-free instrumentation

Testing

• .\gradlew.bat check compileShaders