test: exercise the API gate with a breaking change

[jcant0n]

Throwaway. Renames one public enum member to confirm the gate reports breaking and withholds the merge. Will be closed once the verdict is in.

[github-actions]

API gate: breaking

This removes or changes public symbols. Merging is left to a human — a rename is sometimes the right answer, but never an automatic one.

Target framework	Added	Removed
net10.0	+1	-1

net10.0 — 1 symbol(s) gone

K Evergine.Bindings.Vulkan.StdVideoH264Level.STD_VIDEO_H264_LEVEL_1_0 = 0

net10.0 — ApiCompat reported binary incompatibility

CP0002: Member 'Evergine.Bindings.Vulkan.StdVideoH264Level Evergine.Bindings.Vulkan.StdVideoH264Level.STD_VIDEO_H264_LEVEL_1_0' exists on .api-gate/base/net10.0.dll but not on .api-gate/head/net10.0.dll

_{Enum and constant values are part of the measured surface: a renumbering keeps compiling and sends the wrong number to the driver, so it counts as a removal.}

[jcant0n]

Verdict was correct: breaking, the removed symbol named, ApiCompat corroborating, merge withheld. Throwaway, closing.