`pinoc build` now runs the entrypoint check after `cargo build-sbf`,
fails naming the feature that enabled `no-entrypoint`, and deletes the
artifact. `pinoc deploy` checks the `.so` it is about to upload,
however it was built. The check tests the ELF entry address against the
executable sections, as the SBF loader does, and is shared by build,
test, and deploy in src/commands/artifact.rs.