[biosed]

Summary

• report Ampere special register 0x84 as a 1 x 1 fragment (bytes 1 and 2)
• make any other unknown S2R/S2UR register visible in translator notes before preserving the existing zero fallback
• add Linux-runnable SPIR-V regressions for both S2R and S2UR, the byte product, and the diagnostic

This is the source-only adaptation of seedds/nxnative#2373 for the Vulkan/native-mesh branch. No title-derived bytes or rebuilt tool binaries are included.

Evidence

• new translator: test_dmsh_fragment_size.py 4/4 pass
• previous d83 translator: the same 4/4 fail
• test_dmsh_ampere_mesh.py: 11/11 pass
• test_dmsh_shared_spill.py: 4/4 pass
• owned Ocarina package, outside git: 195 unique pixel-shader keys read SR84; old/new rebuild and Vulkan 1.3 validation succeed for all 195, and all 195 outputs change
• native task/mesh corpus: 520/520 translate and Vulkan 1.3 validate; byte-identical to the current vector3 translator outputs
• record-relative scan of the whole mapped corpus found no other unknown S2R/S2UR register; raw package-wide candidates were non-instruction bytes

Upstream reference: seedds/nxnative#2373