fix(fill-style): correct pattern orientation by flipping texture y-axis (Fixes #10548) - #10550

Fix pattern orientation in FillStyleExtension

Problem

FillStyleExtension renders patterns flipped vertically (top-to-bottom) compared to the original asset. A line pattern going from bottom-left to top-right (/) appears as bottom-right to top-left (\).

Root cause

The texture coordinate system has y=0 at the bottom (OpenGL convention), but the geometry coordinates have y increasing upward. When computing texCoords from patternUV (which is derived from geometry coordinates), the y-axis was not flipped, causing the pattern to appear inverted.

Fix

Flip the y-axis of patternUV when computing texture coordinates:
```glsl
// Before
vec2 texCoords = fill_patternBounds.xy + fill_patternBounds.zw * patternUV;

// After
vec2 texCoords = fill_patternBounds.xy + fill_patternBounds.zw * vec2(patternUV.x, 1.0 - patternUV.y);
```

Breaking change

This fix changes the visual output of FillStyleExtension for all users who rely on the current (incorrect) pattern orientation. The issue author noted this is a breaking change, but the fix aligns the rendering with the principle of least surprise — patterns should render in the same orientation as the original asset.

Closes #10548