# PLAN: S5 — 聊天列表页

## Goal
新增 AI 聊天页面 `/chat`，包含左侧会话列表 + 右侧消息区域。

## Current
- `chat.html` exists but serves WeChat talker chats (different layout)
- No `/chat` (without talker) route for AI chat
- S2 APIs exist: GET /api/conversations (list), POST /api/conversations (create)

## Tasks
1. Add `@app.route("/chat")` → renders new `aichat.html` template
2. Create `aichat.html`:
   - Left sidebar (260px): "+ 新建对话" button + scrollable conversation list
   - Right area: placeholder for S6's chat interface
   - JS: fetch /api/conversations, render list, click to select, new button POSTs

## Files
- `app.py`: add route
- `templates/aichat.html`: new template

## Verification
- curl /chat → HTTP 200 + HTML contains sidebar elements
- Smoke test passes