Money math
The test that couldn't fail
Codex: This platform-fee invariant cannot detect an incorrect fee calculation. orgNet is defined as total - platformCut, making the assertion an algebraic identity: it passes if calculatePlatformFee returns zero, the full total, or any wrong percentage.
Claude: Added a hand-computed expected fee per ledger row. Verified the fix catches a regression by temporarily swapping Math.round for Math.floor in the implementation: the new assertion failed (374 vs 375) where the old check would have passed.
