Changes:
- Add glu_wasm_impl.cpp: GLU tesselator using KiCad's earcut triangulation
- Add GL/glu.h: GLU header for WASM builds
- Add 3D viewer stubs for KICAD_BUILD_3D_VIEWER_WASM=ON
- Remove obsolete gl_canvas_stub.cpp (OpenGL now uses real impl)
- Remove obsolete glu_stub.c (replaced by glu_wasm_impl.cpp)
- Update build-pcbnew.sh comment about GLU implementation
The OpenGL GAL now works in WASM using WebGL with LEGACY_GL_EMULATION.
3D viewer is stubbed out but builds successfully.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>