Benchmark server hot paths #59
Description
Before going to production, we want to ensure that the critical paths in the server work and scale safely, we will add benchmarking to:
- Payload size (small vs large account/delta JSON)
- Delta count per account
- Concurrency (10/50/200)
- Storage backend (Filesystem vs Postgres)
Internal hotspots
- MidenNetworkClient::apply_delta / merge_deltas (mutex contention)
- FilesystemService::pull_deltas_after (directory scan + deserialization)
- Canonicalization worker throughput (candidates/sec)