TrustSignal v0.7.0

TrustSignal v0.7.0

• Replace the toy Halo2 mock prover with real proof generation and verification flow in circuits/non_mem_gadget, wiring both the non-membership and revocation circuits through the new shared helper so they emit verified proofs rather than MockProver artifacts.
• Harden the /api/v1/receipt/:receiptId/revoke endpoint in apps/api by adding a dedicated issuer-signature pre-handler, expanding revocation test coverage, and ensuring Fastify requests carry the verified issuer context before mutating DB state.
• Clean up README links so every reference is relative to the repo instead of machine-local paths, and document the proof/receipt integration steps for the next product push.