[Contracts] Implement Virtual Yield Accrual Logic

[ONEONUORA]

Description

Write yield accumulation math directly on the smart contract:

• Track virtual interest accretion based on blocks/time elapsed since last_ping or creation.
• Keep calculations integer-safe to prevent overflow bugs.

Acceptance Criteria

• Calculate yield accurately based on target yield rate.
• Prevents overflows using safe arithmetic libraries.
• Compares yield values with tests.

[drips-wave]

Congratulations, @ejioforJs! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @ejioforJs: 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.

Warning

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[ONEONUORA]

@ejioforJs
Pls update on this issue
You will be unassign in 6 hours

[Meme11030]

@Meme11030 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer I will like to work on this issue

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[Kappa16]

@Kappa16 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Plea5se maintainer..I can handle this professionally and make sure this issue is closed ASAP WITHOUT ERRORS.

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[Ebenezer199914]

@Ebenezer199914 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

i will love to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ebenezer199914 to this issue.