Add ArkForge Trust Layer — certifying proxy for MCP tool calls

[desiorac]

ArkForge Trust Layer is an open-source certifying proxy for MCP tool invocations.

It sits between the LLM and MCP servers and produces a tamper-evident receipt per tool call, chaining each receipt to the previous via HMAC. The chain proves ordering, non-repudiation, and parameter integrity across a session.

What it does:

• HMAC-chained receipts per tools/call binding method + params hash + timestamp + caller identity
• Ed25519 signatures per receipt
• RFC 3161 timestamp anchoring (verifiable without trusting the proxy)
• Sigstore Rekor transparency log integration
• Independently verifiable: receipts can be checked without access to the proxy

Compliance angle:
EU AI Act Article 14 requires tamper-evident audit trails for high-risk AI systems. A mutable log doesn't satisfy this requirement. Trust Layer's chained receipts do.

Repo: https://github.com/ark-forge/trust-layer
API: https://trust.arkforge.tech