Orphaned test: block_producer_startup_is_robust_to_network_failures

[huitseeker]

The file crates/block-producer/src/server/tests.rs exists but is never compiled. There's no mod tests; in mod.rs.

The test also uses outdated APIs (BlockProducer struct fields, GenesisState::new signature, Store struct) that have changed since the test was written.

Options:

• Delete the orphaned file
• Update the test to match current APIs and add #[cfg(test)] mod tests; to mod.rs