Validate Stellar strkey addresses

[Manuel1234477]

Context

STELLAR_GATEWAY_PUBLIC (src/config.rs) and merchant_id/addresses are accepted as raw strings. A typo in the gateway key silently produces unpayable intents; invalid input is never rejected.

Tasks

• Add strkey validation (correct G... prefix, length, base32 + CRC16 checksum) — via the stellar-strkey crate or a small local validator.
• Reject startup if STELLAR_GATEWAY_PUBLIC is set but invalid.
• Validate any user-supplied Stellar addresses at the API boundary.

Acceptance criteria

• Invalid gateway key fails fast at boot with a clear error.
• Unit tests cover valid and corrupted strkeys.

[xx7412421-cloud]

/claim #6

I would like to work on this issue. If assigned, I will add focused Stellar strkey validation for configured gateway/merchant addresses, reject invalid values with clear non-secret errors, and include regression tests for valid and invalid public keys.

I will wait for assignment or explicit maintainer confirmation before opening a PR.

[Darkdruce]

Hi Maintainer Can I work on this issue to implement validate stellar strkey addresses
I have experience with such issues

[grantfox-oss]

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

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #6)
2. Your PR will be reviewed by the StellarGateLabs 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 campaign!

@Darkdruce's PR #57 was approved and merged by @Manuel1234477.

🏆 @Darkdruce: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (191 total points). Track your full progress on GrantFox.

👏 Great work, @Darkdruce! Keep contributing to StellarGateLabs.