perf(bootstrap): Reduce Bootstrap CSS de 227KB a 145KB con PurgeCSS

- Genera bootstrap-subset.min.css con solo clases usadas (36% reduccion)
- Actualiza enqueue-scripts.php para usar el subset
- Agrega scripts de build: npm run build:bootstrap
- Mejora LCP al reducir tiempo de parseo CSS

Impacto estimado:
- Bootstrap: 227KB -> 145KB (-82KB)
- Tiempo parseo CSS: ~800ms -> ~500ms
- LCP: mejora esperada ~300-500ms

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package.json

@@ -0,0 +1,26 @@
+{
+  "name": "roi-theme",
+  "version": "1.0.0",
+  "description": "WordPress theme con Clean Architecture para analisisdepreciosunitarios.com",
+  "main": "index.js",
+  "scripts": {
+    "build:bootstrap": "node build-bootstrap-subset.js",
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/prime-leads-app/roi-theme.git"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/prime-leads-app/roi-theme/issues"
+  },
+  "homepage": "https://github.com/prime-leads-app/roi-theme#readme",
+  "description": "",
+  "devDependencies": {
+    "glob": "^13.0.0",
+    "purgecss": "^7.0.2"
+  }
+}