[2026 Testing] Add property-based tests for XDR and amount boundaries

[Nanle-code]

Objective

Verify round trips and rejection behavior across extreme amounts, memos, time bounds, and operation sets.

Target area

transaction utilities and builders

Acceptance criteria

• The objective is implemented with clear handling for invalid input, unsupported environments, and failure paths.
• Automated tests cover the primary flow, at least one boundary case, and at least one failure case.
• User-facing documentation or developer guidance is updated, including compatibility, security, or migration notes where applicable.

Source: .github/roadmap-issues-2026-07-29.json.

[jaymoneymanxl]

@jaymoneymanxl has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I would love to work on this, Please assign it to me

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

[Ugooweb]

@Ugooweb has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Please assign this issue to me my eta is 4 hours

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

[drips-wave]

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

🧑‍💻 @jaymoneymanxl: 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 completed by @jaymoneymanxl as part of the Stellar Wave Program's 7th Wave 🥳

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