Correct Non-Parimutuel Payout Logic

[hman38705]

issues : 2

Great issue: Correct Non-Parimutuel Payout Logic

Description
The implementation in claim_winnings contains let winnings = bet.amount;, which only returns the user's original stake upon winning. The core value proposition of a prediction market—where winners split the pool of losers—is broken, leading to "trapped" capital (losers' stakes) that can never be claimed and removing all financial incentive for participation.

Requirements and context

• Implement pool-ratio based payout math: winnings = (bet.amount * total_staked) / winning_outcome_stake.
• Ensure rounding favors the protocol (e.g., truncate down).
• Must be efficient and easy to review.

Suggested execution

• Fork the repo and create a branch: git checkout -b fix/issue-2-payout-math
• Implement the parimutuel formula in the winnings calculation.

Implementation changes

• Update bets.rs (around line 140) to calculate proportional winnings instead of returning the stake.

Test and commit

• Run tests with varied stake amounts to ensure correct distribution.
• Validate that the total balance of the contract remains consistent after all claims.

Example commit message
fix: implement parimutuel payout logic in claim_winnings

Guidelines

• Clear documentation for mathematical assumptions.
• Timeframe: 72 hours.

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[Manuel1234477]

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This issue has been completed by @Manuel1234477 as part of the Stellar Wave Program's 3rd Wave 🥳

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