Use project directory name as MCP server name in monorepos

[20syldev]

Problem

In a monorepo with multiple Nuxt apps, every dev server writes its MCP entry under the same key ("nuxt") in .cursor/mcp.json, .vscode/mcp.json, and .mcp.json. Starting app B overwrites app A's entry, leaving only one server registered at a time.

Fix

Derive updateConfigServerName from the project's root directory basename instead of hardcoding 'nuxt':

- updateConfigServerName: 'nuxt',
+ const defaultServerName = `nuxt-${basename(nuxt.options.rootDir)}`
+ // ...
+ updateConfigServerName: defaultServerName,

Result for a monorepo with apps/web and apps/admin:

{
  "mcpServers": {
    "nuxt-web":   { "url": "http://localhost:3000/__mcp/sse" },
    "nuxt-admin": { "url": "http://localhost:3001/__mcp/sse" },
    "nuxt-docs":  { "url": "https://nuxt.com/mcp" }
  }
}

Each app gets its own stable key. Users can still set updateConfigServerName explicitly in nuxt.config to override the default.

Fixes #31