[SDK] Prepare `planVerification` and agent client flows for formal integrity enforcement

[Solomonsolomonsolomon]

Turn current plan verification and agent client semantics into a stronger integrity model with signed approvals, tamper detection, and clearer client-side verification responsibilities.

[victorocheje]

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

I would like to work on this issue

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

[manueldezman]

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

Hello maintainer, i would like to work on this, will submit a PR within 1 hour, kindly assign to me

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

[owohdora-stack]

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

Hi maintainer am active to resolve this issue, have gone through it and will carry out the task perfectly and diligently
Kindly assign this to me thanks

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[michaelvic123]

@michaelvic123 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

please assign this issue to me

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[drips-wave]

Congratulations, @michaelvic123! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @michaelvic123: 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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