docs: 重写 README 界面预览,换新 UI 的 1920×1080 截图

- hero 图换成新首页;预览网格改为画图台/概览/模型/渠道/用户/日志六张
- 删除账号池时代的 accounts.png,新增 channels.png、users.png
- 去掉"深/浅双主题"描述(现为固定浅色),用户端补"无限画布"
- README.en.md 补上此前缺失的截图区,与中文版对齐

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README.en.md

@@ -20,10 +20,43 @@
 
 [Live Demo](https://vividai.run) · [Features](#-features) · [Deploy](#-deployment) · [API](#-vivid-protocol-api)
 
+<br/>
+
+<img src="docs/screenshots/home.png" alt="image2api — landing" width="860" />
+
 </div>
 
 ---
 
+## 🖼️ Screenshots
+
+<div align="center">
+<sub>✨ Vivid-style light UI · channel routing · data-driven ops dashboard</sub>
+</div>
+
+<table>
+  <tr>
+    <td width="33%"><img src="docs/screenshots/playground.png" alt="Studio" /></td>
+    <td width="33%"><img src="docs/screenshots/dashboard.png" alt="Dashboard" /></td>
+    <td width="33%"><img src="docs/screenshots/models.png" alt="Models" /></td>
+  </tr>
+  <tr>
+    <td align="center"><b>🎨 Studio</b><br/><sub>image + video · reference uploads · live pricing</sub></td>
+    <td align="center"><b>📊 Dashboard</b><br/><sub>users / volume / channel health / 24h trend</sub></td>
+    <td align="center"><b>🧩 Models</b><br/><sub>channel bindings + weights · standard + reseller pricing</sub></td>
+  </tr>
+  <tr>
+    <td width="33%"><img src="docs/screenshots/channels.png" alt="Channels" /></td>
+    <td width="33%"><img src="docs/screenshots/users.png" alt="Users" /></td>
+    <td width="33%"><img src="docs/screenshots/logs.png" alt="Logs" /></td>
+  </tr>
+  <tr>
+    <td align="center"><b>🔌 Channels</b><br/><sub>save-to-sync upstream models · live balance · failover</sub></td>
+    <td align="center"><b>👥 Users</b><br/><sub>roles / concurrency groups / credits · batch ops</sub></td>
+    <td align="center"><b>📜 Logs</b><br/><sub>success / failed / running · prompts and latency kept</sub></td>
+  </tr>
+</table>
+
 ## ✨ Introduction
 
 **image2api** is a homogeneous gateway. Upstream, it connects any number of **vivid-protocol (vividai) instances** as "channels" and routes jobs across them. Downstream, it exposes the same **vivid-protocol API** to callers: `POST /v1/generate` (NDJSON stream) · `POST /v1/uploads` (presigned upload) · `GET /v1/models` · `GET /v1/balance`. No built-in provider code, no account pools — an upstream is just another vividai instance, so gateways can be layered arbitrarily.

README.md

@@ -22,7 +22,7 @@
 
 <br/>
 
-<img src="docs/screenshots/playground.png" alt="image2api — 画图台" width="860" />
+<img src="docs/screenshots/home.png" alt="image2api — 首页" width="860" />
 
 </div>
 
@@ -54,18 +54,28 @@
 ## 🖼️ 界面预览
 
 <div align="center">
-<sub>🎨 现代化画图前端 · 深 / 浅双主题管理后台 · 数据驱动的运营看板</sub>
+<sub>✨ Vivid 风格浅色界面 · 渠道化调度 · 数据驱动的运营看板</sub>
 </div>
 
 <table>
   <tr>
+    <td width="33%"><img src="docs/screenshots/playground.png" alt="画图台" /></td>
     <td width="33%"><img src="docs/screenshots/dashboard.png" alt="概览看板" /></td>
     <td width="33%"><img src="docs/screenshots/models.png" alt="模型管理" /></td>
+  </tr>
+  <tr>
+    <td align="center"><b>🎨 画图台</b><br/><sub>生图 / 生视频一站式 · 参考图上传 · 实时计价</sub></td>
+    <td align="center"><b>📊 概览看板</b><br/><sub>用户 / 生成量 / 渠道健康 / 24h 趋势</sub></td>
+    <td align="center"><b>🧩 模型管理</b><br/><sub>渠道绑定与权重 · 普通价 + 代理价 · 配价即上架</sub></td>
+  </tr>
+  <tr>
+    <td width="33%"><img src="docs/screenshots/channels.png" alt="渠道管理" /></td>
+    <td width="33%"><img src="docs/screenshots/users.png" alt="用户管理" /></td>
     <td width="33%"><img src="docs/screenshots/logs.png" alt="调用日志" /></td>
   </tr>
   <tr>
-    <td align="center"><b>📊 概览看板</b><br/><sub>用户 / 生成量 / 渠道健康 / 24h 趋势</sub></td>
-    <td align="center"><b>🧩 模型管理</b><br/><sub>按模型独立配置能力、定价与权重,配价即上架</sub></td>
+    <td align="center"><b>🔌 渠道管理</b><br/><sub>保存即全量同步上游模型 · 余额实时探测 · 故障转移</sub></td>
+    <td align="center"><b>👥 用户管理</b><br/><sub>角色 / 并发组 / 积分 · 批量选中操作</sub></td>
     <td align="center"><b>📜 调用日志</b><br/><sub>成功 / 失败 / 进行中 · 提示词与耗时全留痕</sub></td>
   </tr>
 </table>
@@ -104,7 +114,7 @@
 #### 🖥️ 用户前台(Vue 3)
 - 画图台 · 创作记录画廊 · 生成日志(含失败原因 / 来源标签)
 - 作品画廊**多选批量操作**:全选本页 / 批量删除 / 批量下载(自动打包 zip)
-- **充值 · 订单** · API 文档 · API Key 管理 · 邀请 · 亮 / 暗主题
+- **充值 · 订单** · API 文档 · API Key 管理 · 邀请 · 无限画布
 - **站内公告**:登录后自动弹出 Markdown 公告
 
 #### 🛠️ 管理后台