feat: Add reentrancy protection for external contract calls

[cypriannwokolo2-creator]

Description

Reentrancy attacks are a critical security vulnerability. All contracts need reentrancy protection when invoking external contracts.

Requirements

• Implement reentrancy guard in common/src/reentrancy.rs
• Add reentrancy checks to functions that invoke external contracts
• Add tests for reentrancy scenarios

Acceptance Criteria

• Reentrancy guard prevents recursive calls
• All external contract invocations use reentrancy protection
• Tests verify reentrancy is blocked

Priority

High

[Fading-Dev]

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

Hello maintainer inepullike to work on this

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

[Femaleotaku]

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

Hello, I'd like to pick this issue up.

I'll implement this carefully with security as the primary concern, sticking closely to the acceptance criteria and avoiding scope creep.

Planned approach, based on the acceptance criteria:

• Reentrancy guard prevents recursive calls
• All external contract invocations use reentrancy protection
• Tests verify reentrancy is blocked

I'd love the opportunity to work on this — please consider assigning it to me.

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

[6akola]

@6akola has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Please, assign me this issue.
Thank you....

ℹ️ Repo Maintainers: To accept this application, review their application or assign @6akola to this issue.

[Ceepr1an]

@Ceepr1an has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would like to work on this one

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ceepr1an to this issue.

[drips-wave]

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

🧑‍💻 @Femaleotaku: 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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