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/.devcontainer/devcontainer.json

@@ -0,0 +1,49 @@
+{
+  "name": "Chatwoot Development Codespace",
+  "service": "app",
+  "dockerComposeFile": "docker-compose.yml",
+
+  "settings": {
+    "terminal.integrated.shell.linux": "/bin/zsh",
+    "extensions.showRecommendationsOnlyOnDemand": true,
+    "editor.formatOnSave": true,
+    "files.trimTrailingWhitespace": true,
+    "files.insertFinalNewline": true,
+    "search.exclude": {
+      "**/node_modules": true,
+      "**/tmp": true,
+      "**/log": true,
+      "**/coverage": true,
+      "**/public/packs": true
+    }
+  },
+
+
+  // Add the IDs of extensions you want installed when the container is created.
+  "extensions": [
+    "Shopify.ruby-lsp",
+    "misogi.ruby-rubocop",
+    "davidpallinder.rails-test-runner",
+    "github.copilot",
+    "mrmlnc.vscode-duplicate"
+  ],
+
+
+  // 5432 postgres
+  // 6379 redis
+  // 1025,8025 mailhog
+  "forwardPorts": [8025, 3000, 3036],
+
+  "postCreateCommand": ".devcontainer/scripts/setup.sh && POSTGRES_STATEMENT_TIMEOUT=600s bundle exec rake db:chatwoot_prepare && pnpm install",
+  "portsAttributes": {
+    "3000": {
+      "label": "Rails Server"
+    },
+    "3036": {
+      "label": "Vite Dev Server"
+    },
+    "8025": {
+      "label": "Mailhog UI"
+    }
+  }
+}