feat(mcp): add doctor command

Add the MCP doctor subcommand with text and JSON output, config-only mode, and scope filtering so users can diagnose MCP issues from the CLI.

Co-Authored-By: Claude <noreply@anthropic.com>

src/commands/mcp/doctorCommand.test.ts

@@ -0,0 +1,19 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+import { Command } from '@commander-js/extra-typings'
+
+import { registerMcpDoctorCommand } from './doctorCommand.js'
+
+test('registerMcpDoctorCommand adds the doctor subcommand with expected options', () => {
+  const mcp = new Command('mcp')
+
+  registerMcpDoctorCommand(mcp)
+
+  const doctor = mcp.commands.find(command => command.name() === 'doctor')
+  assert.ok(doctor)
+  assert.equal(doctor?.usage(), '[options] [name]')
+
+  const optionFlags = doctor?.options.map(option => option.long)
+  assert.deepEqual(optionFlags, ['--scope', '--config-only', '--json'])
+})