Merge pull request 'perf(shaders): drop nonuniformEXT on text font slots' (#80) from claude/issue-49 into master

shaders/ui-text.comp.glsl

@@ -36,9 +36,12 @@ void main() {
         vec2 t  = (sp - it.rect.xy) / it.rect.zw;
         vec2 uv = mix(it.uv.xy, it.uv.zw, t);
 
+        // Font slots are push constants — provably dynamically uniform, so no
+        // nonuniformEXT: lets the compiler hoist the descriptor load out of the
+        // per-pixel glyph loop and avoid the divergent-descriptor path.
         float sdf = texture(
-            sampler2D(uiTextures[nonuniformEXT(pc.fontTextureSlot)],
-                      uiSamplers[nonuniformEXT(pc.fontSamplerSlot)]),
+            sampler2D(uiTextures[pc.fontTextureSlot],
+                      uiSamplers[pc.fontSamplerSlot]),
             uv
         ).r;