`manage_hub::subscription` — subscription cancellation does not emit a cancellation event

[Nabeelahh]

• Area: Smart Contract
• Description: cancel_subscription updates the subscription status in storage but a review of the module should confirm whether an event is published. If it is missing, add env.events().publish(...) so indexers can track cancellations without polling storage.
• File(s): contracts/manage_hub/src/subscription.rs
• Priority: Medium
• Implementation & verification: Treat this as a protocol-safety change: check authorization, storage/ABI compatibility, ledger-time behavior, and emitted events before changing the implementation. Add a contract-level regression test for both the invalid and successful paths.
• **Required change set **: Change the relevant contract implementation together with its focused contract test, and include a type, error, or deployment-script adjustment only when required.

[Cedarich]

@Cedarich has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello maintainer can i take up this

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[drips-wave]

Congratulations, @Cedarich! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @Cedarich: 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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[drips-wave]

This issue has been marked as completed by a Drips Wave moderator for @Cedarich as part of the Stellar Wave Program's 8th Wave 🥳

Moderator's reason: [Auto-assessed] PR #321 has been merged by maintainers (mergedAt: 2026-08-26T12:57:51Z) and received an explicit APPROVAL review from maintainer @Qoder-Voidd. The PR content successfully addresses issue #279 by ensuring subscription cancellation emits the proper event and includes a focused regression test (test_cancel_subscription_emits_event).

😎 @Cedarich: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here.

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ℹ️ Note: This issue was marked complete via moderation. Points were issued even though the GitHub issue remains open.