refactor: Simplify sort in GfxRenderer::fillPolygon (#1817)

## Summary

Small simplification to node sorting algorithm in
GfxRenderer::fillPolygon.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**NO**_

lib/GfxRenderer/GfxRenderer.cpp

@@ -5,6 +5,8 @@
 #include <Logging.h>
 #include <Utf8.h>
 
+#include <algorithm>
+
 #include "FontCacheManager.h"
 
 const uint8_t* GfxRenderer::getGlyphBitmap(const EpdFontData* fontData, const EpdGlyph* glyph) const {
@@ -882,16 +884,8 @@ void GfxRenderer::fillPolygon(const int* xPoints, const int* yPoints, int numPoi
       j = i;
     }
 
-    // Sort nodes by X (simple bubble sort, numPoints is small)
-    for (int i = 0; i < nodes - 1; i++) {
-      for (int k = i + 1; k < nodes; k++) {
-        if (nodeX[i] > nodeX[k]) {
-          int temp = nodeX[i];
-          nodeX[i] = nodeX[k];
-          nodeX[k] = temp;
-        }
-      }
-    }
+    // Sort nodes by X
+    std::sort(nodeX, nodeX + nodes);
 
     // Fill between pairs of nodes
     for (int i = 0; i < nodes - 1; i += 2) {