ACP Build Plan — SDK, Enrichment, and Spec Website

ACP (Atomic Content Protocol) is a planned system comprising three workstreams: an open-source SDK monorepo with core schema validation, LLM-powered enrichment pipelines, and MCP server packages; enrichment tools integrated into Stacklist MCP that use a single LLM call to generate tags, summaries, classifications, and key entities for content objects; and a dedicated spec website. The SDK architecture extracts and generalizes existing Stacklist MCP code into reusable packages (@acp/core, @acp/enrichment, @acp/mcp) with a CLI, supporting multiple AI providers, filesystem-based storage, tiered enrichment depth levels, and 15 MCP tools for creating, enriching, searching, and managing Atomic Content Objects.