[Easy] Add docs/MCP_USAGE.md mcp.json snippet for Cursor

[hoainho]

🌟 Before claiming this issue

Two quick steps before you open a PR:

1. ⭐ Star the repository — low-friction signal that you'll follow through
2. 💬 Comment I'll take this (or similar) below — prevents two contributors racing on the same issue

Full policy: CONTRIBUTING.md → How to claim. If a claim is older than 7 days with no PR, you can reclaim it politely.

---

Context

MCP server v1 launches with mcp.json snippets for Claude Desktop and opencode (see openspec/changes/mcp-server-v1/tasks.md task 5.2). Cursor is the third most common MCP client and deserves a working snippet.

Where to look

• File: cli/docs/MCP_USAGE.md (created by task 5.2)
• Add a "## Cursor" section under existing Claude Desktop + opencode sections
• Document the path Cursor expects for MCP config (typically ~/.cursor/mcp.json or workspace .cursor/mcp.json)
• Snippet must reference @nhonh/react-debugger@latest mcp subcommand

Expected outcome

• ## Cursor section in cli/docs/MCP_USAGE.md
• Valid JSON snippet that works when pasted into Cursor MCP settings
• At least one screenshot of Cursor showing react-debugger tools loaded

Estimated effort

S (1–2h)

How to claim

Comment @hoainho I will take this to claim. PR within 10 days or unclaimed.

Acceptance criteria

• Cursor MCP settings render the react-debugger toolset after pasting the snippet
• get_fiber_node callable from Cursor agent on a real React app
• No new secrets/keys committed

[kauercurtis]

@hoainho I will take this

[kauercurtis]

@hoainho I am kind of confused on how much work this issue is? So I do have the .cursor JSON file good to go but the problem is that the actual code in the repo doesn't create a local MCP server that Cursor can use. And based on the link given to MCP server 1 working (it is a dead link) I am curious if you could link how those work because as far as I can see, they shouldn't work.