feat(cli): add Cursor MCP integration support

[prosdev]

🎯 Overview

Adds --cursor flag to MCP commands to support Cursor IDE alongside Claude Code. Users can now seamlessly install and manage dev-agent MCP server in Cursor with automatic workspace detection and proper process cleanup.

✨ Features

• ✅ Cursor config utilities (read/write ~/.cursor/mcp.json)
• ✅ --cursor flag on install, uninstall, and list commands
• ✅ Smart server name generation with conflict resolution
• ✅ Duplicate detection - prevents installing twice for same repository
• ✅ Shows ALL MCP servers in list (not just dev-agent)
• ✅ Idempotent operations - safe to run multiple times
• ✅ Dynamic workspace detection - single server adapts to open workspace
• ✅ Zombie process prevention - properly cleans up when window closes

🚀 Usage

# Install for Cursor
dev mcp install --cursor
# Output: Creates 'dev-agent-{reponame}' server in ~/.cursor/mcp.json

# List all MCP servers in Cursor
dev mcp list --cursor
# Shows: Figma, dev-agent, and any other configured servers

# Uninstall from Cursor
dev mcp uninstall --cursor
# Removes dev-agent server for current repository

# Default behavior (Claude Code) unchanged
dev mcp install

🏗️ Implementation

New Cursor Config Module

Created packages/cli/src/utils/cursor-config.ts with:

• readCursorConfig() - Read Cursor MCP config (creates if missing)
• writeCursorConfig() - Write config with atomic operations
• generateServerName() - Generate unique names (dev-agent-{repo})
• addCursorServer() - Add server with duplicate detection
• removeCursorServer() - Remove server by repository path
• findServerByRepository() - Find existing server
• listCursorServers() - List all MCP servers (not just dev-agent)

Updated MCP Commands

All commands now support --cursor flag:

• Default behavior: Uses Claude Code (claude CLI)
• With --cursor: Directly manipulates ~/.cursor/mcp.json

Dynamic Workspace Detection

Problem: Original implementation used static REPOSITORY_PATH, causing MCP server to stay locked to one workspace even when switching windows.

Solution: Prioritize WORKSPACE_FOLDER_PATHS environment variable (Cursor's dynamic workspace indicator):

// MCP server entry point now detects workspace dynamically
const repositoryPath = 
  process.env.WORKSPACE_FOLDER_PATHS ||  // Cursor's dynamic workspace
  process.env.REPOSITORY_PATH ||         // Static fallback
  process.cwd();                         // Final fallback

Impact: Single dev-agent MCP server now adapts to whatever workspace is open in Cursor!

Zombie Process Prevention

Problem: MCP server processes weren't terminating when Cursor closed windows, leading to zombie process accumulation.

Solution: Added stdin closure handlers in StdioTransport:

// Handle stdin closure (when IDE closes)
this.readline.on('close', () => {
  process.exit(0);
});

process.stdin.on('end', () => {
  process.exit(0);
});

Testing: Verified with real Cursor windows - process count correctly decreases when windows close.

🧪 Testing

• ✅ 20 tests for Cursor config utilities, all passing
• ✅ Comprehensive coverage of all operations
• ✅ Tests for duplicate detection
• ✅ Tests for HTTP vs stdio server types
• ✅ All existing tests still passing
• ✅ Manually tested dynamic workspace switching
• ✅ Manually tested zombie process cleanup

📊 Test Coverage

Test Files  1 passed (1)
     Tests  20 passed (20)

Tests include:

• Config file read/write with missing files
• Server name generation with conflicts
• Add server with duplicate detection
• Remove server by repository path
• List all servers (HTTP and stdio types)
• JSON formatting validation

🎨 User Experience

Install - Already Exists

$ dev mcp install --cursor
ℹ MCP server already installed in Cursor!

Server name: dev-agent-my-repo
Repository: /Users/user/workspace/my-repo

Run dev mcp list --cursor to see all servers

Install - Success

$ dev mcp install --cursor
✔ MCP server installed in Cursor!

Integration complete! 🎉

Server name: dev-agent-my-repo
Available tools in Cursor:
  dev_search  - Semantic code search
  dev_status  - Repository status
  dev_plan    - Generate development plans
  dev_explore - Explore code patterns
  dev_gh      - Search GitHub issues/PRs

Repository: /Users/user/workspace/my-repo
Storage: ~/.dev-agent/indexes/a1b2c3d4

⚠️  Please restart Cursor to apply changes

List - Multiple Servers

$ dev mcp list --cursor

MCP Servers in Cursor:

  Figma
    Command: HTTP: https://mcp.figma.com/mcp

  dev-agent
    Command: dev mcp start
    Repository: /Users/user/workspace/dev-agent

Total: 2 server(s)

Dynamic Workspace Switching (NEW!)

# Open dev-agent repo in Cursor → Use dev_status
Repository: /Users/user/workspace/dev-agent (128 files)

# Open lytics-lab repo in new window → Use dev_status
Repository: /Users/user/workspace/lytics-lab (456 files)

# Close lytics-lab window
# Process properly terminates, no zombies! ✅

🔗 Related

Closes #58
Related: #61 (CLI improvements for future)

📝 Follow-up

Created #61 for additional CLI improvements:

• --yes flag for non-interactive mode
• --format json for machine-readable output
• --dry-run for preview mode
• Standardized exit codes