Implement Apply for Slot on Multi-Winner Milestone bounties

[Benjtalkshow]

On a MULTI_WINNER_MILESTONE bounty, the sidebar CTA shows an "Apply for Slot [Coming soon]" button that runs a stub click handler. Contributors can't actually apply for a slot, and the slot counter on the bounty card never moves.

We need a real apply action that increments the slot occupancy and adds the contributor to the milestone funnel.

What to do

Add a useApplyForSlot mutation in hooks/use-bounty-application.ts accepting bountyId and applicantAddress. Optimistically:

• Increment totalSlotsOccupied on the bounty detail in the cache
• Append the applicant to contributorProgress at the first milestone
• Roll back on error

In components/bounty-detail/bounty-detail-sidebar-cta.tsx (both SidebarCTA and MobileCTA), replace the stub click handler with a call to the new mutation. Drop the [Coming soon] suffix from the button label and disable the button only when the slot count is full, the user is already in contributorProgress, or the session doesn't have a wallet address.

Acceptance criteria

• Eligible contributor can click Apply for Slot and join the bounty
• totalSlotsOccupied / maxSlots count on the sidebar and the bounty card reflects the new count after applying
• Contributor's avatar appears in the milestone funnel
• Button reads "Slots Full" and disables when the bounty is at capacity
• Button reads "Already Joined" and disables for an applicant already in the bounty

Files

• components/bounty-detail/bounty-detail-sidebar-cta.tsx
• hooks/use-bounty-application.ts

[linear]

BOU-229

[coderabbitai]

🔗 Related PRs

#111 - Feat: implementation logic for single claim model [merged]
#178 - Feat/competition bounty flow [merged]
#180 - test(e2e): add Playwright bounty application flow test [merged]
#186 - Implement Multi-Winner Milestone Bounty Flow (Issue #173) [merged]
#200 - Feat/bounty selection flow model 2 [merged]

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[Michaelkingsdev]

@Michaelkingsdev has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello, can i work on this task? I have contributed to this repo before.

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

[nonso7]

@nonso7 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello good day. Can i work on this issue

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[JohnOluB]

@JohnOluB has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I’ll start by replacing the dummy button logic with a real useApplyForSlot mutation that adds the user to the bounty and updates the UI immediately. I’ll make sure it updates the slot count, adds the user into the first milestone, and rolls back if anything fails.

Then I’ll wire it into both the sidebar and mobile CTA, remove the “Coming soon” label, and properly disable the button when the bounty is full or the user already joined.

I’ve worked with optimistic UI updates before, and I’ll make sure this feels fast, clean, and consistent across BoundlessFi.

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

[thebabalola]

@thebabalola has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintainer, I'm a Stellar developer with extensive experience building application flows for multi-winner bounties. I can implement the Apply for Slot feature for the Multi-Winner Milestone bounties, ensuring a smooth and intuitive process for contributors. Ready to dive in once assigned!

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

[whisper011]

@whisper011 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Gm! I'd like to work on this.

I've gone through the issue and understand what needs to be done. I'll keep the fix scoped, clean, and tested — and communicate clearly if anything comes up along the way.

Ready to start immediately. Feel free to assign it!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @whisper011 to this issue.

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Congratulations, @Michaelkingsdev! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Michaelkingsdev: 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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[Ishant5436]

Fixed in earlier commits