Add MCP server: expose agentlang as Model Context Protocol

[fractlrao]

Summary

• Adds an MCP server that mounts on the existing Express app at /mcp (configurable) when mcpServer.enabled is set in app config.
• Maps every @public event to a module__event tool and every entity to module__Entity__{create,list,get,delete} tools and an agentlang://module/Entity resource.
• Adds a built-in agentlang_search_tools tool that ranks available tools by query so clients can discover tools without listing them all.
• Reuses bearer-token auth via verifyAuth and threads the session into tool handlers via AsyncLocalStorage.
• Stateless transport per request by default (matches SDK guidance); stateful Map<sessionId, transport> mode available via mcpServer.stateless: false.

Config

{
  "service": { "port": 8080 },
  "auth": { "enabled": true },
  "mcpServer": {
    "enabled": true,
    "path": "/mcp",
    "expose": { "events": true, "entities": true, "resources": true }
  }
}

Point an MCP client (Claude Desktop, Cursor, etc.) at http://<host>:8080/mcp with Authorization: Bearer <token>.

Test plan

• npx vitest run test/runtime/mcpserver-unit.test.ts — 44 unit tests covering schema mapping, tool naming, search scoring, expose toggles
• npx vitest run test/api/mcpserver.test.ts — 21 integration tests driving the real @modelcontextprotocol/sdk client through tools/list, tools/call (events + entity CRUD), resources/list, resources/read, hot-reload, expose toggles, search, auth gating
• Full npx vitest run — only the pre-existing llm-service.test.ts fails (requires AGENTLANG_ANTHROPIC_KEY); all other tests pass
• npx tsc -b tsconfig.src.json — clean
• npx eslint on changed files — clean
• prettier --write on changed files — clean