Decouple frontend from Rails, establish pnpm workspace dev workflow

Strip the Chatwoot frontend down to a standalone Vite + Vue 3 SPA that talks
directly to the GoChat Go backend — no Ruby/Rails required.

Deleted from frontend/ (all Rails-only):
- Ruby: Gemfile, Gemfile.lock, config.ru, Capfile, Rakefile, bin/ (binstubs),
  config/ (application/boot/environment/routes/initializers/environments/locales),
  app/helpers/ (*.rb), app/views/ (ERB/jbuilder), app/assets/ (administrate scss)
- Enterprise overlay (enterprise/ — pure Ruby/jbuilder, zero JS)
- Infra: Procfile*, docker-compose*, docker/, deployment/, swagger/, .circleci/,
  .devcontainer/, .qlty/, .codegraph/, .windsurf/, .github/, .vscode/, .husky/
- Lint/config: .rubocop.yml, .scss-lint.yml, .rspec, rubocop/, .bundler-audit.yml,
  .annotaterb.yml, .all-contributorsrc, crowdin.yml, histoire.config.ts, etc.
- Stale frontend/pnpm-lock.yaml (replaced by root workspace lockfile)

Kept (frontend build essentials):
- app/javascript/ (all Vue SPA source — dashboard/widget/sdk/portal/superadmin/survey/v3)
- package.json, vite.config.ts, tailwind.config.js, postcss.config.js
- theme/, vitest.setup.js, .prettierrc

Key decoupling changes:
- vite.config.ts: removed vite-plugin-ruby, added explicit rollupOptions.input
  for all 7 entrypoints + dev-server proxy (/api,/platform,/cable,/health → GoChat)
- index.html: created static SPA entry that injects window.chatwootConfig /
  window.globalConfig (previously done by Rails ERB vueapp.html.erb)
- package.json: renamed @gochat/frontend, removed vite-plugin-ruby/histoire/husky,
  scripts now use plain vite dev/build
- tailwind.config.js: removed enterprise ERB content paths
- markdownEmbeds.js: relocated markdown_embeds.yml into app/javascript/dashboard/config/

Root pnpm workspace:
- package.json: dev:backend (air), dev:frontend (vite), dev (concurrently)
- pnpm-workspace.yaml: frontend as workspace package
- .gitignore: node_modules/, frontend/dist/, frontend build artifacts

Verified: pnpm install + vite build succeeds (4446 modules, all 7 entrypoints
produce JS+CSS chunks in dist/).

README.md

@@ -43,12 +43,11 @@ backend/                # Go 后端（单仓库 monorepo 子目录）
   scripts/              # 迁移、种子、健康检查等脚本
   tests/
     e2e/                # 端到端测试（Auth/AccountCRUD/CRM）
-frontend/               # Chatwoot Vue 3 前端（vendor 过来后续定制）
+frontend/               # Chatwoot Vue 3 前端（已从 Rails 解耦，独立 Vite SPA）
   app/javascript/       # Vue SPA 源码（dashboard/widget/sdk/portal/superadmin）
-  app/views/            # ERB 模板（vite-plugin-ruby entrypoint 解析依赖）
-  enterprise/           # 企业版前端覆盖层
-  config/vite.json      # Vite-Rails 桥接配置
-  package.json          # pnpm + Vite + Vue 3 工具链
+  index.html            # 静态入口（注入 window.chatwootConfig）
+  vite.config.ts        # 标准 Vite 配置（dev server 代理 API 到 GoChat 后端）
+  package.json          # @gochat/frontend（pnpm + Vite + Vue 3）
 deploy/                 # 部署相关
   docker/               # Dockerfile + docker-compose（dev/prod/test）
   quickstart/           # 本地/UAT 一键启动 Compose 栈
@@ -107,6 +106,24 @@ docker compose --profile seed run --rm seed
 
 详见 [deploy/quickstart/README.md](deploy/quickstart/README.md)。
 
+### 前端开发
+
+前端已从 Chatwoot 的 Rails 耦合中解耦，现为独立的 Vite + Vue 3 SPA，直连 GoChat 后端。
+
+```bash
+# 仓库根目录统一启动
+pnpm install              # 安装所有 workspace 依赖
+pnpm dev:backend          # 启动 Go 后端（air 热重载，端口 3000）
+pnpm dev:frontend         # 启动 Vite dev server（端口 3036，API 代理到 :3000）
+pnpm dev                  # 同时启动前后端
+
+# 单独构建前端
+pnpm build:frontend       # 生产构建 → frontend/dist/
+```
+
+Vite dev server 会将 `/api`、`/platform`、`/cable`、`/health` 代理到 GoChat 后端
+（默认 `http://127.0.0.1:3000`，可通过 `VITE_API_HOST` 环境变量覆盖）。
+
 ## 环境配置
 
 GoChat 使用 **Viper 多环境叠加**机制：