17. Add read-only preview methods for borrow, withdraw, and health impact

[Cedarich]

Area: Soroban
Complexity: Medium

Summary:
Expose helper reads so clients can preview protocol effects before sending state-changing transactions.

Acceptance Criteria:

• Preview methods return borrowable and withdrawable guidance.
• Health impact can be queried without mutating state.
• Method outputs are documented for integrators.

[Ayinkx]

Hi i would like to work on this issue please assign to me
I can do it perfectly

[Purity-Euphemia]

Good Day Maintainer, I have experience and would review the issue, implement a clean solution, test it, and submit a pull request.

[Ayinkx01]

Hi l would like to take this job

[grantfox-oss]

🦊 GrantFox — @Ayinkx has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #188)
2. Your PR will be reviewed by the Zyntarivoid maintainers

Good luck! Track your progress on GrantFox.