Add fixed-point e18 accrual representation for share-conserving rounding across reports

[thlpkee20-wq]

Description

Accrual today uses bps math, accumulating rounding dust on each report. Switch the internal accrual index to e18 fixed-point and only collapse to integer on claim, eliminating cumulative dust within typical period counts.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: Revora-Contracts/src/lib.rs, Revora-Contracts/src/payout_test.rs
• Conversion to/from e18 must use checked_mul and checked_div consistently

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/e18-accrual-fixed-point
• Implement changes
  • Replace acc_per_share_bps with acc_per_share_e18
  • Update report_revenue index update and claim settlement
  • Add invariant: collapsing all holders' e18 owed sums equals reported revenue
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test --all
• Cover edge cases
  • 10_000 sequential 1-unit reports must not accumulate >1 unit of dust per holder
• Include test output and security notes

Example commit message

feat: switch accrual to e18 fixed-point for tighter rounding

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[ayo-ola0710]

@ayo-ola0710 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hey , pls assign these to me to solve for you

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ayo-ola0710 to this issue.

[grantfox-oss]

🦊 GrantFox — @ayo-ola0710 has been assigned to this issue!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #479)
2. Your PR will be reviewed by the RevoraOrg maintainers

Good luck! Track your progress on GrantFox.

[drips-wave]

Congratulations, @ayo-ola0710! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @ayo-ola0710: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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