Add TWAP valuation oracle for offering NAV computation independent of spot price

[thlpkee20-wq]

Description

Spot-price NAV is manipulable. Add a time-weighted average price (TWAP) accumulator that downstream consumers can read for valuations and concentration checks, sampled by report_revenue and bounded to a configurable window.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: Revora-Contracts/src/lib.rs
• TWAP must be capped at MAX_TWAP_WINDOW_SECS and ignore samples older than the window

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/twap-valuation-oracle
• Implement changes
  • Add TwapAccumulator { last_ts, last_price, cumulative_price_secs }
  • Sample on each report_revenue with payment-token price
  • Expose get_twap(offering_id, window_secs) -> i128
• Validate security and correctness assumptions

Test and commit

• Run tests
  • cargo test --all
• Cover edge cases
  • Identical timestamps must not double-count cumulative price
• Include test output and security notes

Example commit message

feat: add TWAP valuation accumulator for offering NAV

Guidelines

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

[WHIZAB4TECH]

@WHIZAB4TECH has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I’m interested in contributing to this issue and believe I can deliver a clean, well-tested solution that aligns with the project’s standards.

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[Abdulmajeed82]

@Abdulmajeed82 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue pls..

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Abdulmajeed82 to this issue.

[drips-wave]

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