Shader for loop with a negative signed start value never executes on Vulkan and OpenGLES3

Steps to reproduce:
1. Open the attached user's project "reproduce-shader-signedness.zip"
2. Set the Graphics API to Vulkan
3. Enter Play Mode or build for Windows/Android
4. Observe the two cubes

Actual result: The left cube is red — the fragment shader's for loop body never executes
Expected result: Both cubes are green

Reproducible with: 6000.0.1f1, 6000.0.81f1, 6000.3.22f1, 6000.5.8f1, 6000.6.0b9, 6000.7.0a4

Testing Environment: Windows 11
Not reproducible on: no other environment tested

Notes:
-Issue reproduces with Vulkan and OpenGLES3. DX12 and DX11 renders both cubes green
-Workaround 1: add "#pragma use_dxc vulkan" — DXC bypasses HLSLcc and emits signed comparisons (SLessThanEqual)
-Workaround 2: hoist the division into "int center = range / 2;" and loop from -center to center