fix: report direction probability as signal confidence

更新 README 和代码，数据源切换为 Tushare，优化请求重试机制

fix: add retries and timeout for akshare data fetch

更新 README，切换数据源为 AkShare，统一请求字段为 symbol，优化缓存机制，新增性能日志

Include prediction result in cache endpoint response

Rewrite README with proper Markdown formatting

Add optional ts_code filter to GET /api/v1/cache

Add result cache with A-share market-close TTL

Fix RotaryEmbedding race condition in concurrent batch inference

Add batch prediction endpoint

Initial deployment: Kronos stock predictor REST API