Provides wasm/stubs/model_substitution_stub.cpp — no-op IsWrlExtension /
STEP_CATALOG::Build / FindMatchFor — so pcbnew and footprint_editor link when the
3D viewer is off (KICAD_BUILD_3D_VIEWER_WASM=OFF). The KiCad 10 rebase made
dialog_migrate_3d_models.cpp reference these, which live in the unlinked 3D
library. The browser build has no 3D viewer, so model migration finds no
substitutions. Bumps kicad to the matching CMake wiring (fef0343).
Verified: pcbnew + footprint_editor compile and link clean (eeschema/symbol_editor
unaffected).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
