Fix stale closure bug causing incorrect blackjack win/loss determination

[Copilot]

Player with 21 loses to dealer with 17 due to React state closure capturing outdated hand value.

Root Cause

When hit() adds a card and reaches 21, it calls setPlayerHand() then immediately stand(). The 500ms setTimeout in stand() captures the pre-update playerHand closure value. When dealerPlay() executes, it passes this stale hand to endGame(), causing incorrect win/loss evaluation.

Changes

• Thread finalPlayerHand?: Card[] parameter through stand() → dealerPlay() → endGame()
• Pass newPlayerHand from hit() when player reaches 21
• Fallback to state variable when parameter not provided (button clicks, empty deck scenarios)

// Before: stale closure
const hit = () => {
  const newPlayerHand = [...playerHand, newCard];
  setPlayerHand(newPlayerHand);
  if (handValue === 21) stand(); // captures old playerHand
};

// After: thread fresh value
const hit = () => {
  const newPlayerHand = [...playerHand, newCard];
  setPlayerHand(newPlayerHand);
  if (handValue === 21) stand(newPlayerHand); // pass current value
};

const dealerPlay = (finalPlayerHand?: Card[]) => {
  endGame(finalPlayerHand || playerHand, newDealerHand, newDeck);
};

6 lines changed in BlackjackModal.tsx.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Blackjack says I lost when I clearly won</issue_title>
<issue_description>
See attatched image, i got 21, the dealer got 17, and somehow i lost... </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Blackjack says I lost when I clearly won #28

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Project	Deployment	Preview	Comments	Updated (UTC)
mix-click	Ready	Preview	Comment	Dec 7, 2025 8:02am

[mixtapejaxson]

LGTM.