Add AgentBridge — neutral A2A↔MCP/ACP bridge with governance

[shadowhunter-92]

Adding AgentBridge to Tools & Utilities → Other Utilities, next to the existing A2A-MCP-Server entry since it's a sibling (a cross-protocol bridge).

What it is: an open-source (Apache 2.0), neutral bridge that lets any MCP client reach A2A agents — and also ACP, OpenAI/Gemini function-calling, and AGNTCY — through one canonical model. Every protocol adapter is conformance-tested against that protocol's real official SDK (the SDKs disagree on field names in ways that break naive bridges). It also adds an optional governance plane (Ed25519 agent identities, per-agent budgets, hash-chained tamper-evident audit) enforced in the call path, and runs as a drop-in MCP server.

• Repo: https://github.com/shadowhunter-92/agentbridge
• It's directly A2A-related (A2A is one of the six protocols, with a live A2A handshake demo + conformance test against a2a-sdk).
• Early-stage and honestly labeled as a work-in-progress in the README — not promotional, a real tool. Feedback very welcome.

Thanks for maintaining this list!

[shadowhunter-92]

Gentle nudge on this one 🙏 — AgentBridge is a neutral interoperability + governance layer that translates A2A ↔ MCP / ACP / OpenAI / Gemini function-calling, and adds agent identity, per-agent budgets, and a tamper-evident (hash-chained) audit trail directly on the call path. Apache-2.0, CI + tests green, works as a drop-in MCP server or inline proxy. Happy to adjust the entry's wording or category to fit the list better — thanks for maintaining awesome-a2a!