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/api/ApiClient.js

@@ -0,0 +1,63 @@
+/* global axios */
+
+const DEFAULT_API_VERSION = 'v1';
+
+class ApiClient {
+  constructor(resource, options = {}) {
+    this.apiVersion = `/api/${options.apiVersion || DEFAULT_API_VERSION}`;
+    this.options = options;
+    this.resource = resource;
+  }
+
+  get url() {
+    return `${this.baseUrl()}/${this.resource}`;
+  }
+
+  // eslint-disable-next-line class-methods-use-this
+  get accountIdFromRoute() {
+    const isInsideAccountScopedURLs =
+      window.location.pathname.includes('/app/accounts');
+
+    if (isInsideAccountScopedURLs) {
+      return window.location.pathname.split('/')[3];
+    }
+
+    return '';
+  }
+
+  baseUrl() {
+    let url = this.apiVersion;
+
+    if (this.options.enterprise) {
+      url = `/enterprise${url}`;
+    }
+
+    if (this.options.accountScoped && this.accountIdFromRoute) {
+      url = `${url}/accounts/${this.accountIdFromRoute}`;
+    }
+
+    return url;
+  }
+
+  get() {
+    return axios.get(this.url);
+  }
+
+  show(id) {
+    return axios.get(`${this.url}/${id}`);
+  }
+
+  create(data) {
+    return axios.post(this.url, data);
+  }
+
+  update(id, data) {
+    return axios.patch(`${this.url}/${id}`, data);
+  }
+
+  delete(id) {
+    return axios.delete(`${this.url}/${id}`);
+  }
+}
+
+export default ApiClient;