Fix double-emission of OracleResultEvent in resolution.rs fallback path

[greatest0fallt1me]

Description

When the primary oracle fails and the fallback succeeds, resolution.rs emits OracleResultEvent once for the failure and again for the success but with the same market_id and overlapping oracle_provider semantics, which causes downstream indexers to count the resolution twice. Disambiguate by adding attempt: u32 and is_final: bool to the event payload.

Requirements and Context

• Mutate the event schema in events.rs
• Update all emission sites in resolution.rs and oracles.rs
• Update indexer-facing docs
• Must be secure, tested, and documented
• Should be efficient and easy to review

Suggested Execution

1. Fork the repo and create a branch

   git checkout -b bug/oracle-result-event-double-emit

2. Implement changes
   • contracts/predictify-hybrid/src/events.rs
   • contracts/predictify-hybrid/src/resolution.rs
   • Update existing test asserting emission count
3. Test and commit
   • cargo test -p predictify-hybrid oracle_result_event
   • Cover edge cases
   • Include test output and notes in the PR

Example commit message

fix: disambiguate primary/fallback OracleResultEvent emissions

Acceptance Criteria

• Each emission carries unique (attempt, is_final) pair
• Exactly one event with is_final=true per resolved market
• Existing tests updated to assert new schema

Guidelines

• No unwrap() in production paths
• Clear documentation and inline comments
• Timeframe: 96 hours

[MK0042]

@MK0042 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I will like to apply. I understand that it can be difficult to trust someone without a track record, but I will really appreciate the opportunity to demonstrate my skills. I would also be grateful for the chance to earn some points along the way.

Thank you for considering my application.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @MK0042 to this issue.

[drips-wave]

Congratulations, @MK0042! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @MK0042: 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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