Vendor Chatwoot Vue 3 frontend into frontend/

Copy the Chatwoot (v4.14.0) frontend runnable subset into frontend/ for
customization:
- app/javascript/ (Vue SPA: dashboard, widget, sdk, portal, superadmin)
- app/views/ (ERB templates for vite-plugin-ruby entrypoint resolution)
- app/helpers/, app/assets/ (Rails view helpers, static assets)
- enterprise/ (Enterprise edition frontend overlay)
- config/vite.json, vite.config.ts, bin/vite (Vite-Rails toolchain)
- package.json, pnpm-lock.yaml, tailwind/postcss/eslint configs
- Gemfile, Gemfile.lock (vite_rails gem for bin/vite binstub)

Excluded Rails backend: controllers, models, services, jobs, mailers,
policies, db, lib, spec, public, node_modules.

Update references to the new frontend location:
- .gitignore: exclude frontend build artifacts (node_modules, tmp, packs),
  keep frontend/bin/ and frontend/vendor/ via negation
- backend/scripts/parity_frontend_smoke.sh: CHATWOOT_DIR default
  reference/chatwoot -> ../frontend
- backend/scripts/parity_frontend_browser_smoke.mjs: same default update
- AGENTS.md: add frontend section with Rails/Vite coupling notes
- README: architecture tree includes frontend/

frontend/app/javascript/dashboard/components/policy.vue

@@ -0,0 +1,36 @@
+<script setup>
+import { usePolicy } from 'dashboard/composables/usePolicy';
+import { computed } from 'vue';
+
+const props = defineProps({
+  as: {
+    type: String,
+    default: 'div',
+  },
+  permissions: {
+    type: Array,
+    required: true,
+  },
+  featureFlag: {
+    type: String,
+    default: null,
+  },
+  installationTypes: {
+    type: Array,
+    default: null,
+  },
+});
+
+const { shouldShow } = usePolicy();
+
+const show = computed(() =>
+  shouldShow(props.featureFlag, props.permissions, props.installationTypes)
+);
+</script>
+
+<!-- eslint-disable vue/no-root-v-if -->
+<template>
+  <component :is="as" v-if="show">
+    <slot />
+  </component>
+</template>