feat: add MCP server for tool-agnostic AI integration

[CoderMungan]

Implement Model Context Protocol (JSON-RPC 2.0 over stdin/stdout) server that exposes ctx context as MCP resources and tools.

Resources: 7 context files + assembled agent packet
Tools: ctx_status, ctx_add, ctx_complete, ctx_drift

All tools delegate to existing internal packages — no duplicated logic. Works with Claude Desktop, Cursor, VS Code Copilot, and any MCP-compatible client.

[josealekhine]

Thanks for your contributions @CoderMungan 🙏

This is a great proof-of-concept.

I'll come up with details.

[josealekhine]

Before I beat this to the ground here are the strength in this PR that I see:

• Clean separation: protocol.go (types), server.go (dispatch), resources.go (read), tools.go (write) — well-organized
• Delegates to existing internal packages (context.Load, drift.Detect, task, add.WriteEntry) instead of reimplementing logic
• Good test coverage (337 lines) with table-driven-ish patterns and a reusable request() helper
• Correctly uses config.FileReadOrder, config.FileType, config.RegExTask — plays by the project's rules
• Injectable in/out on Server makes testing clean
• Follows project conventions: copyright headers, doc.go, Godoc format, constants from config.

Expext constructive criticisim, and a hint of ctx-Manifesto-driven opinions next :D .

--

To be clear; this is the right path. I do want to land it.

I just want to land the the right way: The ctx way, if you will.

[josealekhine]

@CoderMungan I've added some outstanding items to be done before a "minimally delightful" PR merge; and also scooped our near and mid future of the capability here: https://github.com/ActiveMemory/ctx/blob/main/specs/mcp-server.md

Thank you again for your valuable contribution 🙏 .