security: audit & replace all Math.random in transaction / id / hash generation

[nanaf6203-bit]

Summary

Use of Math.random() in IDs, hashes, and security-sensitive contexts (covered in #1) has been found in many call sites; consolidate as a security hardening epic.

Affected area

Search for Math.random in src/** and tests/e2e/**.

Steps to reproduce / impact

See issue #1. Aggregating all sites into one issue makes the impact visible.

Expected behaviour

Replace every Math.random (especially substr-based id generation) with crypto.randomUUID or crypto.getRandomValues.

Acceptance criteria

• Close sub-issues once the corresponding Math.random is replaced.
• Add a CI grep check that fails if a new Math.random is added in security-sensitive paths.

[Pascdav001]

@Pascdav001 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello boss, Please assign this issue to me. i checked it out and im confident i will solve it
my eta is 4 hours

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Pascdav001 to this issue.

[DanielCharis1]

@DanielCharis1 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

can i be assigned this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @DanielCharis1 to this issue.

[drips-wave]

Congratulations, @DanielCharis1! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @DanielCharis1: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

This issue has been completed by @DanielCharis1 as part of the Stellar Wave Program's 6th Wave 🥳

😎 @DanielCharis1: 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. You can also Leave a review to share your experience working on this issue.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.