feat: add mcp server (load, unload, export tools + registry)

[yelizhenden-mdb]

Proposed changes

Jira ticket: CLOUDP-393141

Introduces a new MCP server that enables AI agents to manage OpenAPI specifications in memory. Built with the official MCP Go SDK.

Technical design can be found here

Features

Tools

1. load - Load OpenAPI specs from files into memory

2. unload - Remove specs from memory by alias

3. export - Export loaded/virtual specs to JSON or YAML files

Core Components

Registry (internal/registry/)

• Thread-safe in-memory storage for OpenAPI specs
• Supports both file-based and virtual specs
• Collision detection and checksum validation

Tool Handlers (internal/tools/)

• Type-safe handlers using MCP SDK's typed handler pattern
• Clean separation: SDK adapters in tools.go, business logic in separate files

FOASCLI Integration (tools/cli/pkg/openapi/)

• Refactored existing FOASCLI code to export SaveToFile() function
• Shared OpenAPI processing logic between FOASCLI and MCP server

Checklist

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works

Changes to Spectral

• I have read the README file for Spectral Updates

Further comments

The following components will be introduced in subsequent PRs:

• Remaining tools
• Resources
• Binary generation

[cveticm]

on mcp side, lgtm!

[andmatei]

LGTM great work!