Add SDK contract ID registry design

[El-swaggerito]

Description

Difficulty: Expert

Type: Feature

Summary

Design a contract ID registry pattern for managing known PocketPay contract addresses by network.

Current Behaviour

Consumers may hardcode contract IDs inconsistently.

Expected Behaviour

The SDK should provide a safer configuration pattern for known contract IDs.

Suggested Implementation

Create a design or implementation for network-scoped contract ID configuration and validation.

Files or Areas Likely Affected

src/config/
src/soroban/
src/vault/
docs/

Acceptance Criteria

• Contract ID registry pattern is defined.
• Network-specific IDs are supported.
• Invalid IDs are rejected.
• Documentation explains configuration.
• Tests cover lookup and validation.

Additional Notes

Avoid hardcoding production claims if not ready.

[Mubking-dev]

Hi, I'm Mubarak — a Full-Stack & Blockchain Developer with 3+ years of experience. I've reviewed this issue and I'm confident I can handle it. I'll submit a clean PR within 2–3 days. Please assign it to me!

[grantfox-oss]

🦊 GrantFox — @Mubking-dev 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 #218)
2. Your PR will be reviewed by the Axionvera maintainers

Good luck! Track your progress on GrantFox.