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/widget/components/GroupedAvatars.vue

@@ -0,0 +1,36 @@
+<script setup>
+import Avatar from 'dashboard/components-next/avatar/Avatar.vue';
+import { computed } from 'vue';
+
+const props = defineProps({
+  users: {
+    type: Array,
+    default: () => [],
+  },
+  limit: {
+    type: Number,
+    default: 4,
+  },
+});
+
+const usersToDisplay = computed(() => props.users.slice(0, props.limit));
+</script>
+
+<template>
+  <div class="flex">
+    <span
+      v-for="(user, index) in usersToDisplay"
+      :key="user.id"
+      :class="index ? 'ltr:-ml-4 rtl:-mr-4' : ''"
+      class="inline-block rounded-full text-white shadow-solid"
+    >
+      <Avatar
+        :name="user.name"
+        :src="user.avatar_url"
+        :size="36"
+        class="[&>span]:outline [&>span]:outline-1 [&>span]:outline-n-background"
+        rounded-full
+      />
+    </span>
+  </div>
+</template>