144 tests across the SDK

Hit 144 tests across the zera-sdk monorepo today. Coverage is decent on note, commitment, nullifier, and the Groth16 verifier glue; thinner on the Solana-side CPI dispatch, which is where the integration matrix is going to be painful.

The shape of the test pyramid is wrong: too many unit tests, not enough end-to-end. Need a bun test:e2e lane that boots a local solana-test-validator + deploys the verifier program + signs a real proof. That’s the next milestone.