v1.5.6

Fixed

• Fixed SpriteAssist mesh generation in -batchmode -nographics environments. Sprite geometry and texture sub-asset meshes are now generated through a deterministic CPU-only image resampling path instead of GPU Blit/ReadPixels operations.
• Prevented headless build imports from silently falling back to Unity's default rectangular sprite geometry.
• Bumped the texture import postprocessor version to invalidate cached artifacts generated by the previous import path.

Diagnostics

• Geometry-generation failures now produce explicit import errors with the asset path, mesh mode, render type, graphics device, import-worker state, and batch-mode state.
• Added a headless geometry verification entry point and regression coverage for default-rectangle fallback detection.

Verification

• Verified equivalent geometry generation with both Direct3D11 and the Null graphics device (-nographics).