模拟交易与投资平台规格

构建一个名为 "Paper" 的模拟交易（paper trading）平台——一个逼真且零风险的学习环境，帮助用户掌握交易与投资技能。

核心功能：
- 投资组合设置：用户起始资金为 100,000 美元虚拟现金。通过 Yahoo Finance 或 Alpha Vantage API 获取实时股票和 ETF 价格
- 交易执行：支持市价单和限价单。市价单模拟 0.1% 的滑点。每笔交易收取 1 美元佣金（体现真实摩擦，但不具惩罚性）
- 业绩仪表盘：损益图表（按日）、总回报率、年化回报率、胜率、平均盈利与亏损、夏普比率以及当前行业持仓敞口——所有指标在每次交易后更新。使用 recharts 构建
- 交易日志：每次平仓时必须填写字段——“我进入这笔交易的逻辑是什么？发生了什么？我下次会有什么不同做法？” 三个字段，每个最多 200 个字符。未完成日志则无法平仓
- 行为分析：{{llm_api}} 分析最近 20 条交易日志条目，识别重复出现的行为模式——例如“当持仓接近整数价位时，你总是过早退出盈利头寸”——每月生成一次并展示
- 排行榜：可选功能，每周重置的好友群排行榜——按风险调整后收益排序，而非原始盈亏额

技术栈：React、Yahoo Finance 或 Alpha Vantage 获取市场数据、{{llm_api}} 实现行为分析、recharts。终端风格设计——信息密集，无装饰性元素

Build a paper trading simulation platform called "Paper" — a realistic, risk-free environment for learning to trade and invest.

Core features:
- Portfolio setup: user starts with $100,000 in virtual cash. Real-time stock and ETF prices via Yahoo Finance or Alpha Vantage API
- Trade execution: market and limit orders supported. Simulate 0.1% slippage on market orders. Commission of $1 per trade (realistic friction without being punitive)
- Performance dashboard: P&L chart (daily), total return, annualized return, win rate, average gain and loss, Sharpe ratio, and current sector exposure — all updated with each trade. Built with recharts
- Trade journal: required field on every position close — "What was my thesis entering this trade? What happened? What will I do differently?" Three fields, each max 200 characters. Cannot close a position without completing the journal
- Behavioral analysis: {{llm_api}} analyzes the last 20 trade journal entries and identifies recurring behavioral patterns — "You consistently exit winning positions early when they approach round-number price levels" — surfaced monthly
- Leaderboard: optional, weekly-resetting leaderboard among friend groups — ranked by risk-adjusted return, not raw P&L

Stack: React, Yahoo Finance or Alpha Vantage for market data, {{llm_api}} for behavioral analysis, recharts. Terminal-inspired design — data dense, no decorative elements.