Preserve intraday closing-auction bar dropped by Yahoo schedule end

[dokson]

Summary

Closes #1585.

Yahoo's tradingPeriods.end undershoots the real session close on several exchanges by omitting the closing auction. Yahoo still returns a bar at index == end holding the auction price, but fix_Yahoo_returning_prepost_unrequested was discarding it via index >= end, leaving users without the official close.

The reporter's case was Saudi (2222.SR), but a sweep of the major venues found the same pattern on at least 8 exchanges plus US half-days:

Exchange	Yahoo end	Notes
SAU (Tadawul)	15:00 AST	actual close incl. auction is 15:20
KSC (KOSPI)	15:00 KST	closing auction 15:20–15:30
SAO (B3)	17:00 BRT	closing call to ~17:55
BUD (BSE)	17:00 CET
NZE (NZX)	17:00 NZST
SES (SGX)	17:00 SGT	closing routine 17:00–17:06
JNB (JSE)	17:00 SAST
DFM (Dubai)	15:00 GST
US half-days	13:00 EST	Thanksgiving etc.

In every case Yahoo returns a bar at exactly end with a valid Close and Volume == 0, i.e. the closing-auction print. The Volume == 0 part is acknowledged as a Yahoo data limitation in the original issue thread (auction volume not exposed intraday) and is out of scope for this PR.

Changes

• yfinance/utils.py: switch the drop boundary in fix_Yahoo_returning_prepost_unrequested from quotes.index >= quotes['end'] to quotes.index > quotes['end']. Single-character semantic change. Pre-market bars are still pruned by the other half of the filter; bars strictly past end (post-close) still get dropped.
• tests/test_prices.py:
  • test_fix_prepost_keeps_closing_auction_bar — synthetic, no-network regression test exercising both sides of the boundary (pre-market and post-close still drop, bar at == end survives).
  • test_intraday_closing_auction_bar_saudi — live integration check on 2222.SR.
  • test_prune_post_intraday_us assertion relaxed from < to <=: the half-day closing-auction bar at the early-close timestamp is now preserved, which is the intended behavior.

Behavior before

>>> yf.Ticker('2222.SR').history(period='5d', interval='1h').tail(2)
                              Close     Volume
2026-05-07 13:00:00+03:00     27.18    1489165
2026-05-07 14:00:00+03:00     27.12    2800336    # 15:00 closing-auction bar dropped

Behavior after

>>> yf.Ticker('2222.SR').history(period='5d', interval='1h').tail(2)
                              Close     Volume
2026-05-07 14:00:00+03:00     27.12    2800336
2026-05-07 15:00:00+03:00     27.20          0    # closing-auction print preserved

Test plan

• python -m unittest tests.test_prices.TestPriceHistory.test_fix_prepost_keeps_closing_auction_bar tests.test_prices.TestPriceHistory.test_intraday_closing_auction_bar_saudi tests.test_prices.TestPriceHistory.test_prune_post_intraday_us tests.test_prices.TestPriceHistory.test_prune_post_intraday_asx -v — all pass
• TDD red→green: both new tests fail on dev (verified by reverting just the >=/> change), pass with the fix
• Spot-checked the 8 affected exchanges plus AAPL (US, unaffected) — closing-auction bars now appear, no spurious post-market bars