feat(examples): add audit trail forensic export bridge with independent verification (#65)

[Santia2004]

Closes #65

Summary

Implements the Forensic Audit Hub Bridge example under examples/audit-forensic-bridge/ demonstrating:

• Ingestion of webhook events via an Express listener.
• Direct raw JSON SHA-256 calculation (sha256(JSON.stringify(record))) without key-sorting to preserve insertion order matching the Nirium server specification.
• Domain-separated agent attestation (nirium-audit-v1:<content_sha256>) signed with an ed25519 Stellar keypair.
• Automated IPFS anchoring using Agent.anchorAuditRecord().
• Scheduled/manual export and independent verification (src/export.ts): pulls Agent.getReportingExport('anchors'), retrieves raw content from IPFS gateways, and independently re-verifies SHA-256 and agent signatures rather than trusting API metadata.
• Unit test suite covering raw hashing behavior, valid attestations, tampered record detection, and domain separation enforcement.
• Plain-terms README explaining why recomputing hashes locally prevents signature forgery.

Verification

• Unit tests: npx tsx --test test/bridge.test.ts (4/4 passing).

[Eras256]

Merged — verified independently from a clean clone, not just reading the diff. computeRecordSha256 uses a plain JSON.stringify, no key-sorting, and the test proves it (hash changes on key reorder — exactly the failure mode a canonicalizer that alphabetizes would hide). verifyAuditAttestation recomputes from the record rather than trusting an embedded claim. 4/4 tests pass from pnpm install + pnpm test on a fresh checkout. Good work — this is exactly the discipline the issue asked for.