Build mobile queue buddy marketplace list and request creation flow

[S-Mubarak]

Description

The buddy feature needs a user-facing marketplace to be demoable.

Scope

• Add screens for browsing open buddy requests
• Add request creation form attached to a location
• Render status and fee summaries

Acceptance Criteria

• User can create a buddy request from mobile
• User can browse available requests near them
• Request status updates after creation without full app restart

Dependencies

Blocked by: #133

Stack

React Native / Express