bb-v1.1.3

feat(mega): cache compile-only keys and expose ID API

- add bb_acir_compile_mega_honk / bb_mh_prove_with_id / bb_mh_verify_with_id and cache Mega proving/verification keys in-process (in-place refresh optional, default off)

- surface compile_mega/prove_with_id/verify_with_id in aztec-barretenberg-rs, prefer prebuilts in build.rs, and switch batch_merge regression + fixtures to the ID flow

- embed ACIR/witness fixtures, drop Nargo from tests, and add a bench harness exercising the new ID flow

Usage:\n  let key_id = bb::compile_mega(acir_bytes)?;\n  let proof = bb::prove_with_id(&key_id, witness_bytes)?;\n  let ok = bb::verify_with_id(&key_id, &proof.0)?;