library: miuix-blur: clarify render-effect uniform-caching comments

Creation-time uniform capture makes a built effect safe to reuse; distinct shader keys keep concurrent passes/levels on separate instances. Reword so the two read as complementary, not contradictory. Comment-only, no behavior change.

Author: YuKongA

miuix-blur/src/commonMain/kotlin/top/yukonga/miuix/kmp/blur/BackdropEffectScope.kt

@@ -163,8 +163,9 @@ internal abstract class BackdropEffectScopeImpl :
     internal var cachedBlurResult: RenderEffect? = null
 
     // blendColors()/colorControls() build RenderEffects that don't depend on the animating radius,
-    // so cache them: a fixed tint/adjustment rebuilds once, not per frame. Reuse is safe because a
-    // RenderEffect snapshots its shader's uniforms at creation (see LevelTarget.dsEffects).
+    // so cache them: a fixed tint/adjustment rebuilds once, not per frame. A RenderEffect captures
+    // its shader's uniforms when created, so a built effect is unaffected by later re-sets of the
+    // tree-shared RuntimeShader — reuse across frames and both cross-fade passes is safe.
     internal var cachedBlendColors: BlurColors? = null
     internal var cachedBlendResult: RenderEffect? = null
     internal var cachedColorBrightness: Float = Float.NaN

miuix-blur/src/commonMain/kotlin/top/yukonga/miuix/kmp/blur/DrawBackdropModifier.kt

@@ -225,8 +225,9 @@ private class DrawBackdropNode(
         var cascadeFirstStepScale: Int = 1
 
         // Draw-path RenderEffects cached for reuse while the source size / noise coefficient hold.
-        // A RenderEffect snapshots its shader's uniforms at creation, so reusing the instance is
-        // safe and avoids a native allocation per frame. Two slots cover the deepest cascade (sf=16).
+        // A RenderEffect captures its shader's uniforms when created, so a built instance is
+        // unaffected by later re-sets of the tree-shared RuntimeShader — reuse is safe and saves a
+        // native allocation per frame. Two slots cover the deepest cascade (sf=16).
         val dsKeys = arrayOf("", "")
         val dsW = intArrayOf(-1, -1)
         val dsH = intArrayOf(-1, -1)

miuix-blur/src/commonMain/kotlin/top/yukonga/miuix/kmp/blur/internal/BlurEffect.kt

@@ -36,8 +36,8 @@ private val BLUR_V_KEYS: Array<Array<String>> = Array(MAX_BLUR_TAPS + 1) { n ->
 /**
  * Builds the separable Blur [RenderEffect] (H then V) for an EXPLICIT [downScale] level using the
  * per-axis variances already compensated for that level's box prefilter (see [adjustedVarianceForExp]).
- * The shader cache keys carry [downScale] so two adjacent levels rendered in the same frame (the
- * cross-fade lo/hi passes) never share a Gaussian shader instance and corrupt each other's kernel.
+ * The shader cache keys carry [downScale] so the H/V passes and the cross-fade lo/hi levels each
+ * build from a separate shader instance and never alias each other's uniform arrays.
  */
 internal fun createBlurEffect(
     radiusX: Float,
@@ -64,8 +64,8 @@ internal fun createBlurEffect(
 
     var effect: RenderEffect? = null
 
-    // H / V use distinct cache keys so each pass holds its own uniform state; the _d$downScale
-    // suffix additionally isolates the cross-fade lo/hi levels from one another.
+    // H / V use distinct cache keys so each pass builds from its own shader instance; the
+    // _d$downScale suffix additionally isolates the cross-fade lo/hi levels from one another.
     if (radiusX > 0f) {
         val n = computeBlurParamsInto(adjustedVarianceX, rawScratch, paramOffsets, paramWeights)
         if (n > 0) {