修复同步稳定性与远程视图冲突

fix: Switch to download-based Parquet loading to resolve DuckDB httpfs issues in HF Space

fix: Robust remote Parquet mounting with local list caching

fix: Resolve remote Parquet mounting issues with authentication and explicit file listing

feat: Add market selection dropdown to home screen

fix: Improve stability with cache invalidation and robust DB connection management

fix: Align DUCKDB_PATH with Dockerfile

feat: Complete stock trading simulation system