Step 518: add icon and typography harmonization model

editor/src/IconTypographyHarmonizer.h

@@ -0,0 +1,60 @@
+#pragma once
+// Step 518: Icon + Typography Contrast Harmonization
+
+#include <string>
+#include <vector>
+#include <algorithm>
+
+struct TypographyProfile {
+    float bodySizePx = 14.0f;
+    float headingSizePx = 20.0f;
+    float lineHeight = 1.4f;
+    float weightBody = 450.0f;
+    float weightHeading = 640.0f;
+    float textContrast = 1.0f;
+};
+
+struct IconProfile {
+    float strokePx = 1.5f;
+    float contrast = 1.0f;
+    float opticalSize = 16.0f;
+};
+
+class IconTypographyHarmonizer {
+public:
+    static TypographyProfile darkSurfaceTypography(float density) {
+        float d = std::max(0.8f, std::min(1.4f, density));
+        TypographyProfile t;
+        t.bodySizePx = 14.0f * d;
+        t.headingSizePx = 20.0f * d;
+        t.lineHeight = 1.38f;
+        t.weightBody = 460.0f;
+        t.weightHeading = 650.0f;
+        t.textContrast = 6.4f;
+        return t;
+    }
+
+    static IconProfile iconProfileFor(float density, bool emphasized) {
+        float d = std::max(0.8f, std::min(1.4f, density));
+        IconProfile i;
+        i.strokePx = emphasized ? 1.9f * d : 1.5f * d;
+        i.contrast = emphasized ? 4.5f : 3.4f;
+        i.opticalSize = 16.0f * d;
+        return i;
+    }
+
+    static bool harmonized(const TypographyProfile& t, const IconProfile& i) {
+        return t.textContrast >= 4.5f && i.contrast >= 3.0f &&
+               i.strokePx >= 1.0f && t.headingSizePx > t.bodySizePx;
+    }
+
+    static float rhythmScore(const TypographyProfile& t,
+                             const std::vector<float>& panelDensities) {
+        if (panelDensities.empty()) return 0.0f;
+        float spread = *std::max_element(panelDensities.begin(), panelDensities.end()) -
+                       *std::min_element(panelDensities.begin(), panelDensities.end());
+        float base = 1.0f - std::min(1.0f, spread / 12.0f);
+        float typeBonus = (t.lineHeight >= 1.3f && t.lineHeight <= 1.6f) ? 0.2f : 0.0f;
+        return std::max(0.0f, std::min(1.0f, base + typeBonus));
+    }
+};