[CT-09] Implement event creation and management functions (admin)

[yusuftomilola]

Overview

Implement admin-only functions to create, update availability, and close events in the event_ticketing contract. Work inside contracts/sandbox/event_ticketing/.

Acceptance Criteria

• create_event(env, caller, id, name, capacity, ticket_price, start_time, end_time) is admin-gated
• Validates start_time < end_time and capacity > 0 and ticket_price > 0
• Returns Error::AlreadyInitialized if event ID already exists
• cancel_event(env, caller, event_id) sets event status to Cancelled (admin only)
• close_event(env, caller, event_id) sets status to Closed after event ends (admin only)
• Events are indexed in EventList
• Emits events on creation and status change
• Code compiles with cargo build

[keljoshX]

@keljoshX has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi, i can efficiently implement this. pls assign

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[feyishola]

@feyishola has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi im Feyishola, a software developer with over 4 years of experience. Pls can I handle this issue

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Congratulations, @feyishola! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

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This issue has been completed by @feyishola as part of the Stellar Wave Program's 4th Wave 🥳

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