feat(editor): scatter texture patches for natural surface variety

- Scatter Patches: randomly places texture circles across the terrain
  for natural-looking surface variation (dirt patches, rock outcrops)
- Configurable count, min/max radius, and seed
- Preset buttons for dirt and rock patches
- Uses the existing paint() method with random positions
- Adds visual variety to otherwise uniform terrain texturing

tools/editor/texture_painter.cpp

@@ -2,6 +2,7 @@
 #include "core/logger.hpp"
 #include <algorithm>
 #include <cmath>
+#include <random>
 
 namespace wowee {
 namespace editor {
@@ -321,6 +322,25 @@ void TexturePainter::gradientBlend(const std::string& tex1, const std::string& t
     }
 }
 
+void TexturePainter::scatterPatches(const std::string& texturePath, int count,
+                                     float minRadius, float maxRadius, uint32_t seed) {
+    if (!terrain_ || texturePath.empty()) return;
+    uint32_t texId = ensureTextureInList(texturePath);
+
+    float tileNW_X = (32.0f - static_cast<float>(terrain_->coord.y)) * 533.33333f;
+    float tileNW_Y = (32.0f - static_cast<float>(terrain_->coord.x)) * 533.33333f;
+
+    std::mt19937 rng(seed);
+    std::uniform_real_distribution<float> distX(tileNW_X - 533.33333f, tileNW_X);
+    std::uniform_real_distribution<float> distY(tileNW_Y - 533.33333f, tileNW_Y);
+    std::uniform_real_distribution<float> distR(minRadius, maxRadius);
+
+    for (int p = 0; p < count; p++) {
+        float px = distX(rng), py = distY(rng), pr = distR(rng);
+        paint(glm::vec3(px, py, 0), pr, 0.8f, 0.5f);
+    }
+}
+
 std::vector<int> TexturePainter::erase(const glm::vec3& center, float radius,
                                         float strength, float falloff) {
     if (!terrain_ || activeTexture_.empty()) return {};