Add Cursor-specific setup instructions

[jacksandom]

Add Cursor-specific setup instructions for MCP server

Changes

• Enable MCP Server: Documents the required step to toggle on the MCP server in Cursor Settings

• Authentication with Config Profiles: Explains that Cursor MCP subprocesses don't inherit shell environment variables, so DATABRICKS_CONFIG_PROFILE should be passed via the env block
• Project vs Global Configs: Clarifies that Cursor loads from both ~/.cursor/mcp.json (global) and .cursor/mcp.json (project), and global may take precedence
• Troubleshooting: Adds two new sections for Cursor-specific issues (MCP not loading, auth errors)

[dustinvannoy-db]

LGTM. Thanks!