feat: migrate to pnpm, integrate CodeMirror 6, self-hosted fonts, URL sharing

[cmurestudillos]

• Replace npm with pnpm 11.9.0 (packageManager field, pnpm-lock.yaml)
  • Update Husky hooks to use pnpm exec / pnpm run
  • Delete .eslintrc.json (Angular legacy, never linted React code)
  • Rewrite eslint.config.js with ESLint 9 flat config for React + TypeScript
  • Remove eslint-plugin-jsdoc and eslint-plugin-prettier from devDependencies
  • Integrate CodeMirror 6 (HTML/CSS/JS syntax highlighting, dark/light via Compartment)
  • Add manualChunks in vite.config.ts to split CodeMirror into separate chunk
  • Replace Google Fonts with @fontsource/raleway + @fontsource/fira-code (latin only)
  • Add URL sharing via base64 hash (TextEncoder/TextDecoder, replaceState)
  • Add share button with "¡Copiado!" feedback
  • Fix ConsolePanel: Tailwind dynamic hover classes, JSON object display, run separators
  • Fix iframe: remove deprecated frameBorder attribute
  • Fix loadTemplate/loadProject/resetCode: proper TypeScript types
  • Fix selector reset to "En Blanco" on load/reset
  • Update README with current stack, features, and install instructions
  • Add pr-review.yml workflow
  • Add pnpm-workspace.yaml

[github-actions]

🧪 Code Review Checklist

Antes de hacer merge, revisa:

• He revisado mi propio código
• No hay errores evidentes
• He probado los cambios
• El código sigue buenas prácticas
• No introduzco bugs ni deuda técnica

💡 Recuerda: un buen PR = menos bugs en producción 🚀

[cmurestudillos]

Revisado