marketplace real-time update handler can produce stale state and duplicate bid count increments

[grantfox-oss]

app/marketplace/page.tsxincrementsbidCount` on every websocket update without checking if the bid is actually new. Fix race conditions and stale updates.

• Impacted files: app/frontend/src/app/marketplace/page.tsx, app/frontend/src/hooks/useRealtimeUpdates.ts, app/frontend/src/components/UsernameCard.tsx, app/frontend/src/hooks/marketplaceApi.ts, app/frontend/src/__tests__/**/*.test.tsx, app/frontend/src/components/ListingDetailModal.tsx

[nurudeenheroic]

I'd appreciate the opportunity to contribute to this task. I'll approach it carefully and make sure the implementation is polished and dependable.

[chisomvictorcv-sketch]

Hello maintainer, i have gone through the issues description and I have good knowledge on it kindly assign this to me.

[Alanwiz00]

I'd like to work on this.

I've looked through the realtime bid update flow and understand the race conditions behind the current behaviour. The main issues are that bid counts are incremented optimistically instead of reflecting server state, duplicate websocket echoes can be applied more than once, and subscription churn increases the likelihood of missed or out-of-order updates.

My plan is to:

• Make realtime bid updates carry enough information for the client to apply authoritative server state rather than incrementing locally.
• Replace the current update logic with guarded state updates that ignore stale or duplicate events while handling out-of-order delivery safely.
• Deduplicate websocket echoes for bids initiated by the current user to avoid double-counting.
• Stabilize realtime subscriptions so they aren't recreated unnecessarily during listing updates.
• Apply the same update logic wherever bid data is displayed and add tests covering stale events, duplicate updates, and out-of-order delivery.

I'll keep the implementation focused on the realtime synchronization layer so bid counts remain consistent without changing the existing public API or UI behaviour.

[grantfox-oss]

🦊 GrantFox — @Alanwiz00 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #292)
2. Your PR will be reviewed by the BlockDash-Studios maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@Alanwiz00's PR #300 was approved and merged by @MaryammAli.

🏆 @Alanwiz00: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (48 total points). Track your full progress on GrantFox.

👏 Great work, @Alanwiz00! Keep contributing to BlockDash-Studios.