- both fundamentals vendors accepted curr_date and ignored it, serving a
present-day company profile into a run dated in the past: yfinance via
Ticker.info, Alpha Vantage via OVERVIEW
- that profile has no historical vintage, not even name/sector/industry (which
move when a company renames or is reclassified), so a past curr_date now
withholds it and says why; live runs are unchanged
- the rule lives once in date_window next to the existing look-ahead helpers,
so switching data_vendors between the two cannot reintroduce the leak, and
the guard runs before the request rather than discarding a paid-for response
- point-in-time fundamentals for a past date already come from the balance
sheet, income statement and cash flow tools, which filter on curr_date #1300
