[Feature] GUI Interface

Current Problem

目前 CheckPause 是一个纯命令行（CLI）工具。用户粘贴棋谱、输入问题、查看分析结果都在终端中进行，交互方式不够直观。看不到棋盘，无法直接点击走法进行提问，对局面的感知完全依赖文字描述。

Currently CheckPause is a pure command-line tool. Users paste PGNs, type questions, and view analysis results in a terminal. There is no visual board, no clickable moves, and understanding the position relies entirely on text descriptions.

Proposed Approach

引入基于 Streamlit 的图形界面（GUI），将 CP 的使用体验提升到与主流棋谱分析工具相当的水平。

Introduce a Streamlit-based graphical interface that brings CP's user experience to the level of mainstream chess analysis tools.

Implementation Plan

Layout

页面分为四个区域：

• 左上：棋盘 – 显示当前局面，支持跳转到棋谱中的任意一步。
• 左下：棋谱走法列表 – 显示 PGN 中的所有走法，点击任意一步可跳转到对应局面。
• 右上：用户状态 – 显示当前用户名、最新准确度、分析总局数、进步趋势。
• 右下：对话窗口 – 与 CP 进行自然语言交流，输入问题，获取 AI 讲解。

The page is divided into four sections:

• Top-Left: Chessboard – Displays the current position, with navigation to any move in the game.
• Bottom-Left: Move List – Displays all moves from the PGN; clicking a move jumps to that position.
• Top-Right: User Stats – Shows username, latest accuracy, total games, and improvement trend.
• Bottom-Right: Chat Window – Natural language interaction with CP; ask questions, get AI coaching.

Technology Choice

采用 Streamlit + streamlit-chessboard 实现图形界面。原因：

• Python 原生，与现有代码（engine / ai / profile）无缝对接。
• 无需学习 HTML/CSS/JavaScript。
• 开发速度快，可快速迭代原型。

Use Streamlit with streamlit-chessboard for the GUI. Reasons:

• Native Python, integrates seamlessly with existing (engine / ai / profile) code.
• No need to learn HTML/CSS/JavaScript.
• Fast development, rapid prototyping.

Code Impact

• main.py 将被替换为 app.py（Streamlit 入口）。

• engine.py、ai.py、config.py、profile.py 保持不变。

• 新增依赖：streamlit、streamlit-chessboard（或 python-chess SVG 渲染）。

• main.py will be replaced by app.py (Streamlit entry point).

• engine.py, ai.py, config.py, profile.py will remain unchanged.

• New dependencies: streamlit, streamlit-chessboard (or python-chess SVG render).

Open Questions

• 棋盘交互方式：点击走法列表跳转，还是直接在棋盘上点击棋子走棋？

• 棋盘渲染：使用 streamlit-chessboard 还是 python-chess 直接生成 SVG？

• 分析流程：是否保留“粘贴 PGN → 自动分析”的流程，还是改为“粘贴 PGN → 手动点击分析按钮”？

• 对话历史：是否需要保留当前 Streamlit 会话中的完整对话上下文？

• Board interaction: jump by clicking a move in the list, or play moves directly on the board?

• Board rendering: use streamlit-chessboard or generate SVG directly with python-chess?

• Analysis flow: keep the "paste PGN → auto-analyze" flow, or change to "paste PGN → click analyze button"?

• Chat history: preserve full conversation context within the current Streamlit session?