Replace the retired .so Makefile with the wasm/.bnp convention (build /
verify / archive-check / publish via ninja plugin build), gitignore *.so
and *.bnp artifacts, untrack the committed gotham.so binary, and refresh
the stale [compatibility] block_core constraint to the v0.15 era.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
