fix(shadow): correct comparison sampler from GreaterEqual to LessEqual

With the shadow map cleared to 1.0 (farthest depth from light) and the
shadow pass writing smaller depths for surfaces closer to the light,
the fragment-to-light distance must be <= the stored surface depth for
lit pixels. GreaterEqual was inverted — everything appeared lit with no
shadows rendered.

lib/src/shaders/standard_shader.wgsl

@@ -207,7 +207,7 @@ fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
 
 // Étape 14 (DRAFT 3.2, D5) : PCF shadow factor for this fragment. Reprojects the world position
 // into the shadow light's clip space, converts to depth-map UVs + normalized depth, then averages
-// a 3×3 `textureSampleCompare` neighborhood using the comparison sampler (GreaterEqual). Returns
+// a 3×3 `textureSampleCompare` neighborhood using the comparison sampler (LessEqual). Returns
 // 1.0 when fully lit (or shadows disabled), 0.0 when fully in shadow. The reference depth is
 // pulled toward the viewer by `frame.shadow_params.y` (bias) to suppress acne.
 fn compute_shadow(world_pos: vec3<f32>) -> f32 {