Add NVDA intraday analysis script using Futu OpenD - #1

Motivation

• Provide a lightweight CLI tool to pull NVDA realtime and 1-minute intraday data via Futu OpenD and produce a quick “tonight selloff attribution” summary.
• Enable comparing NVDA to a small benchmark set to distinguish idiosyncratic vs. market/sector-driven moves.
• Export minute-level K-line data to CSV for downstream analysis and reproducibility.

Description

• Add futu_nvda_analysis.py, a new script that connects to Futu OpenD and implements a SymbolSnapshot dataclass and helper functions get_snapshot, get_intraday_bars, detect_selloff_window, and analyze_cross_section to perform the analysis.
• The script fetches market snapshots for US.NVDA plus configurable benchmarks (default US.AMD, US.SMH, US.QQQ), computes percent changes, detects top-5 1-minute drops, and prints a simple attribution judgment.
• CLI options include --host, --port, --date, --benchmarks, and --output_csv, and minute K-lines are exported to the specified CSV (default nvda_intraday_1m.csv).
• Dependencies are documented at the top and include futu and pandas with usage instructions to run the script (e.g. python futu_nvda_analysis.py --date 2026-04-30).

Testing

• No automated tests were run for this change.

Codex Task