Add ToolHive CLI and UI connection options to vMCP quickstart

[danbarr]

Issue

In the vMCP quickstart tutorial (docs/toolhive/tutorials/quickstart-vmcp.mdx:205-218), users are instructed to manually edit their mcp.json file:

{
  "servers": {
    "demo-vmcp": {
      "url": "http://localhost:4483/mcp",
      "type": "http"
    }
  }
}

This approach:

1. Requires users to know the exact file location for their OS
2. Requires manual JSON editing with potential for syntax errors
3. Bypasses the ToolHive CLI and UI which provide better user experiences

Proposed solution

Update the quickstart to provide multiple connection options:

Option 1: ToolHive CLI

toolhive connect demo-vmcp http://localhost:4483/mcp

Option 2: ToolHive UI

Use the ToolHive UI to add the connection (provide brief instructions)

Option 3: Manual configuration

Keep the current manual editing instructions as a fallback

This provides:

• Better user experience for most users
• Automatic configuration file management
• Better error messages and validation
• Consistency with other ToolHive documentation
• Still supports manual configuration for advanced users

Context

From PR #326 review comment by @danbarr