v1.0gpu_alpha

What's Changed

• fix(cuda): repair CUDA backend on the XSCAPE Fields path by @jhputschke in #1
• test(cuda): add MUSIC_CUDA_FORCE_COHERENT to validate the GB10 path by @jhputschke in #2
• Xscape cuda 3 last bits of GPU tuning by @jhputschke in #3
• Fix rk1-boundary swap gate; close 100x GPU-vs-CPU precision gap by @jhputschke in #4
• Xscape cuda cpu part improvements by @jhputschke in #5
• Add gpu tuning extra metal as standard by @jhputschke in #6
• freeze_out_surface = 0: stop without building the freeze-out surface by @jhputschke in #9
• Source term on the GPU path: skip empty fills, bin strings by transverse reach by @jhputschke in #10
• StringFind4: fail loudly on a parameter file without EndOfData by @jhputschke in #11
• Freeze-out surface: parallel over eta slices again, deterministic; store P by @jhputschke in #12
• GPU: vacuum cells at rest, non-finite W/Pi guard with counter (grid freeze in dilute regions) by @jhputschke in #13
• HydroinfoMUSIC::clean_hydro_event: release the store's memory by @jhputschke in #15
• docs/MUSIC_CPU_vs_GPU.md; README: validated against the CPU build, large-scale campaign still missing by @jhputschke in #16
• docs/: GPU port documents moved there, every reference updated; test_metal_input removed by @jhputschke in #17
• MUSIC_CUDA_SYNC selects the host wait; string source with less work per pair by @jhputschke in #18

Full Changelog: v3.1...v1.0