refactor(lit): align WGSL and GLSL clustered-light chunks

[mvaligursky]

Follow-up to #8733. Brings the GLSL clustered-light chunk in line with the WGSL refactor, applies the Samsung-precision workaround to WGSL that was previously only in GLSL, and tightens decoder helper signatures.

WGSL changes (`src/scene/shader-lib/wgsl/chunks/lit/frag/clusteredLight.js`):

• `ClusterLightData` slimmed: removed `flags`, `anglesData`, `colorBFlagsData` from the struct; hoisted them to module-scope temporaries with the same comment that GLSL carries (Samsung precision / corruption issue, Clustered lighting not working on some devices #7800).
• `ClusterLightData` members reordered so each `vec3f` packs with an adjacent 4-byte field into a 16-byte slot (minimises padding for compilers that don't reorder).
• `decodeClusterLightProjectionMatrixData` now returns `mat4x4f` instead of mutating the module-level `lightProjectionMatrix` via side effect; call site assigns the result.
• Remaining `decode*` helpers tightened to take only what they need (`lightIndex: i32` or `biasesData: f32`), or no args at all where they read from module-scope temps.
• One-line comments added to `ClusterLightSpotData` / `ClusterLightAreaData` / `ClusterLightShadowData` explaining when each is decoded.
• Removed four stale `// !!!!!!!!!!!` dev-comment leftovers from the original WGSL port. The code they annotated was already correct.

GLSL changes (`src/scene/shader-lib/glsl/chunks/lit/frag/clusteredLight.js`):

• Same `ClusterLightData` slim-down (removed `halfWidth`, `halfHeight`, `omniAtlasViewport`, `cookieChannelMask`, `shadowBias`, `shadowNormalBias`, `innerConeAngleCos`, `outerConeAngleCos` — now in sub-structs decoded on demand).
• Same `ClusterLightData` member reorder for minimal padding.
• Same three new sub-structs (`ClusterLightSpotData`, `ClusterLightAreaData`, `ClusterLightShadowData`) with matching one-line comments.
• All `decode*` helpers changed from `inout`-mutating to value-returning, taking `int lightIndex` / `float biasesData` / no-args as appropriate.
• `decodeClusterLightCore` returns `ClusterLightData` by value; call site is now `ClusterLightData clusterLightData = decodeClusterLightCore(lightIndex);`.
• `sampleLightTextureF(int lightIndex, int index)` — drops the struct parameter for symmetry with WGSL.

No public API changes. All changes are internal to the lit clustered-light shader chunks. The two backends now have near line-for-line equivalent structures, which makes cross-backend maintenance easier going forward.