Update dependencies to latest Nuxt 2 compatible versions

- Updated Nuxt from 2.14.6 to 2.18.1 (final Nuxt 2 release)
- Updated @nuxt/content from 1.9.0 to 1.15.1
- Updated core-js from 3.8.2 to 3.47.0
- Updated all dev dependencies to latest compatible versions
- Replaced deprecated babel-eslint with @babel/eslint-parser
- Updated ESLint, Prettier, and Stylelint to latest v7/v2/v13 respectively
- Reduced security vulnerabilities from 197 to 55

Site builds and generates successfully. All linting passes.

Author: claude

.eslintrc.js

@@ -5,7 +5,8 @@ module.exports = {
     node: true,
   },
   parserOptions: {
-    parser: 'babel-eslint',
+    parser: '@babel/eslint-parser',
+    requireConfigFile: false,
   },
   extends: [
     '@nuxtjs',