Fix GPU-clustered decals vanishing at steep camera pitch

[Ijtihed]

Objective

Fixes #24918. with GPU clustering on

Solution

When the camera looks steeply down everything visible is closer than the first slice depth so assign_objects_to_clusters clamps the grid's far down to near. calculate_cluster_factors then divides by ln(far / near) == 0 and the factors go infinite.

the shader (cluster_raster.wgsl) rebuilt z_near/z_far back out of those factors with exp() and exp(inf / inf) is NaN so every cluster/object intersection test failed and nothing got clustered. (that rebuild was also broken for single Z slice grids.)

this just passes near/far to the shader directly in a new cluster_z_bounds field on the Lights uniform and drops the shader-side rebuild. #23438 is in the same area but a separate bug.

Testing

madethe issue's scene and rendered it at fixed pitches on Linux/Vulkan (GTX 1660 SUPER) and counted decal pixels. before: 0 decal pixels from -50 to -90 degrees. after: matches the CPU clustering path exactly at every pitch. the interactive repro from #24918 also confirms it (decals gone past ~-50, SPACE toggles CPU clustering and brings them back with the fix both look the same)

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Showcase

straight down (-90) GPU clustering, before vs after:

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