feat: setup frontend con pnpm, vite, react, tailwind y shadcn

Inicializa directorio frontend/ con stack React moderno:
pnpm + vite 8 + react 19 + tailwind v4 + shadcn v4 (base-nova).
Estructura functions/core (TS puro) y functions/ui (componentes React).
El indexer descubre frontend/functions/ y frontend/types/ automáticamente.
Elimina functions/components/ (legacy) y actualiza referencias en
CLAUDE.md y template de componentes.

frontend/components.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "base-nova",
+  "rsc": false,
+  "tsx": true,
+  "tailwind": {
+    "config": "",
+    "css": "src/globals.css",
+    "baseColor": "neutral",
+    "cssVariables": true,
+    "prefix": ""
+  },
+  "iconLibrary": "lucide",
+  "rtl": false,
+  "aliases": {
+    "components": "@/components",
+    "utils": "@/lib/utils",
+    "ui": "@/components/ui",
+    "lib": "@/lib",
+    "hooks": "@/hooks"
+  },
+  "menuColor": "default",
+  "menuAccent": "subtle",
+  "registries": {}
+}