Add acp-bridge: ACP/A2A adapter for self-hosted local AI

[WCHungBlake]

Adds acp-bridge to the registry — a Rust adapter that bridges local LLM backends (Ollama, vLLM, llama.cpp, LM Studio, LocalAI, Jan, Tabby) to the Agent Client Protocol, so air-gapped or on-prem models can be used from ACP clients like Zed and Neovim.

v0.7.0 highlights

• ACP server mode (default) — exposes a local LLM as an ACP-compliant agent over stdin/stdout JSON-RPC 2.0.
• ACP client mode (--client) — also works as an orchestrator that spawns other ACP agents as child processes.
• A2A mode (--a2a) — HTTP server exposing an Agent Card at /.well-known/agent.json.
• Spec-compliance fixes — initialize returns top-level protocolVersion: 1, agentCapabilities.promptCapabilities.image: true, and authMethods: []; session/new accepts mcpServers (previously silently dropped).
• Process group isolation, content blocks, session/load resume support, env-var expansion for child agents.

Release: https://github.com/BlakeHung/acp-bridge/releases/tag/v0.7.0

Distribution

Raw binary downloads from the v0.7.0 GitHub release for four platforms:

• darwin-aarch64, darwin-x86_64, linux-aarch64, linux-x86_64

Windows builds are not yet produced by the release workflow; will be added in a follow-up.

Checklist

• id matches directory name (acp-bridge)
• agent.json valid against schema
• icon.svg is 16x16, monochrome, uses currentColor
• All four archive URLs return 200
• License is OSI (MIT)