Implement queue buddy request model and API lifecycle

[S-Mubarak]

Description

Queue buddy is a differentiating feature in the product vision and should enter MVP in simplified form.

Scope

• Add buddy request entity with requester, location, fee, time window, and status
• Implement create, list, accept, and status endpoints
• Define MVP lifecycle without disputes yet

Acceptance Criteria

• User can create a queue buddy request for a location
• Another eligible user can accept the request
• Status transitions are validated server-side

Dependencies

Blocked by: #99
Blocked by: #108

Stack

Express

[GideonBature]

@GideonBature has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Greetings, Please I will love to work on this issue.

I have experience building on stellar.

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

[Thosine-01]

@Thosine-01 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hi! I’d love to lead the implementation of the Queue Buddy MVP. I have extensive experience building Express-based backends with complex entity lifecycles and state-driven logic. I’ll start by architecting a robust QueueBuddyRequest entity that captures all the essential metadata—from location and fees to the specific time windows—ensuring the data layer is ready to scale beyond the MVP.

I will develop a strict server-side state machine to manage request transitions, guaranteeing that every "Accept" or "Complete" action is validated against the current status of the request. My plan includes building a clean, performant set of endpoints for creating and listing requests, optimized so that eligible buddies can find and respond to opportunities in real-time. I’ll also ensure that the foundational logic is "Dispute-Ready," meaning the data structure I build now will easily support the addition of review and conflict resolution systems in future iterations.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Thosine-01 to this issue.