- Introduces new Windows ARM64 jobs in the multi-platform workflow (build, test, retest, gtest).
- Extends composite GitHub actions with a `target-arch` input and adds ARM64 Mesa llvmpipe setup for headless rendering.
- Adjusts architecture reporting (`dversion`) and updates one mesh regression test with ARM64-specific expected values; updates a DE enum definition to avoid an MSVC ARM64 LTCG miscompile.
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