refactor(bbapi): migrate bb binary to ipc-codegen + ipc-runtime

[charlielye]

Summary

Migrates the bb server surface (bbapi, api_msgpack, bb CLI, WASM cbind, and IPC bench paths) to /ipc-codegen + /ipc-runtime.

This PR sits after wsdb migration and before the Rust and bb.js client migrations.

Stack

1. feat(ipc): add /ipc-codegen and /ipc-runtime foundation packages #23610 cl/ipc-foundation
2. refactor(wsdb): migrate aztec-wsdb to ipc-codegen + ipc-runtime #23611 cl/ipc-wsdb-migrate
3. refactor(bbapi): migrate bb binary to ipc-codegen + ipc-runtime #23612 cl/ipc-bb-migrate — this PR
4. refactor(barretenberg-rs): migrate to ipc-codegen + ipc-runtime; drop PipeBackend #23613 cl/ipc-bb-rs-migrate
5. refactor(bb.js): migrate to ipc-codegen + ipc-runtime; delete legacy bb::ipc #23614 cl/ipc-bb-js-migrate
6. refactor: cut-over to new wsdb package - comms over uds ipc. #23036 cl/ipc-3-avm-wsdb-cutover
7. feat: add generated aztec-vm-sim package setup #23084 cl/ipc-4-avm-binary
8. feat: cut simulator over to generated bb-avm-sim IPC service #23697 cl/ipc-5-avm-cutover

What changes

• Commits bb_schema.json and bb_curve_constants.json beside bbapi.
• Generates bb C++ IPC client/server/types from the schema during CMake builds.
• Routes api_msgpack through codegen-emitted make_bb_handler and ipc_runtime server helpers.
• Keeps handle_* functions operating on wire commands, with explicit conversion only where bb domain types are required.
• Removes duplicate domain DTOs and stale wire/domain conversion helpers that were not used.
• Preserves BBApiException semantics for generated error responses.
• Exposes bb msgpack schema from codegen schema reflection.
• Adds generated IPC coverage to C++ CI targets.
• Updates bb.js native binary resolution to the arch-package model: wrapper code resolves bb and nodejs_module.node from installed or sibling arch packages, not from mutable build/ fallbacks.

Notes

The legacy barretenberg/cpp/src/barretenberg/ipc/ transport remains until the bb.js NAPI substrate migrates in #23614. This PR migrates the bb server surface but does not yet delete the old transport.

Validation

• ninja bb bbapi_tests
• ./bin/bbapi_tests
• ./bin/bb msgpack schema
• barretenberg/ts native/ESM/CJS build path for arch-package binary resolution.
• Root ./bootstrap.sh passed on this branch during stack validation after clearing local cache/quota pressure.

[charlielye]

Superseded by #25362, which lands this work off next as one PR. Envelope ids (the 8-byte request-id frame prefix) landed after these were opened and broke wire compatibility between the old and new stacks, so bb, bb.js and bb-rs have to migrate together and can no longer go in independently. This PR was used as the recipe for it.