[PeerX Backlog # 71] Add SDK helpers for typed error decoding

[ameeribro4-sudo]

Problem Statement
Client SDKs (TypeScript, Python) must know the u32 discriminant for
each PeerXError variant. They parse the raw error and dispatch
manually.

Expected Outcome
The SDK ships a generated errors.ts with named variants mapped to
the error code documented in errors.rs.

Acceptance Criteria

• New bindings/errors.ts checked into peer-sdk/.
• The error code table from errors.rs auto-generates.

Implementation Notes
Use soroban-sdk CLI's bindings command.

Files Affected

• peer-sdk/ (new) — out of scope, but lay groundwork.

Dependencies Issue #73.
Difficulty / Effort 🥑 / M
Labels dx, api

[GBOYEE]

Hi team — I'd like to take this on as part of the GrantFox campaign. I'll implement the SDK/contract helper and open a PR referencing this issue shortly.

[ZionApprove]

please I can work on this.

[grantfox-oss]

🦊 GrantFox — @ZionApprove 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 #71)
2. Your PR will be reviewed by the OpenPeerX maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@ZionApprove's PR #118 was approved and merged by @ameeribro4-sudo.

🏆 @ZionApprove: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (118 total points). Track your full progress on GrantFox.

👏 Great work, @ZionApprove! Keep contributing to OpenPeerX.