[Backend] Fix off-by-one regex in isValidStellarAddress that rejects valid 56-char addresses

[ogazboiz]

Telegram: https://t.me/+DOylgFv1jyJlNzM0

Why this matters

backend/src/utils/stellar.ts exposes isValidStellarAddress, but its regex is ^G[A-Z2-7]{54}$ — that only matches 55 characters total (G + 54). A real Stellar public key is 56 characters (G + 55). The preceding length check on line 33 correctly requires length === 56, so the regex can never match a valid address that passes the length check, making the function reject every valid address.

For comparison, both backend/src/services/remittanceService.ts and frontend/src/app/utils/stellar.ts correctly use {55}.

Verified locally:

G + 55 chars -> length 56
/^G[A-Z2-7]{54}$/.test(addr) === false   // util (wrong)
/^G[A-Z2-7]{55}$/.test(addr) === true    // service/frontend (correct)

Acceptance criteria

• Change the regex in backend/src/utils/stellar.ts from {54} to {55}
• Add a unit test asserting a real 56-char G... address returns true
• Confirm assertValidStellarAddress no longer throws for valid input

Files to touch

• backend/src/utils/stellar.ts

Out of scope

• Refactoring the duplicate validators in other files (tracked separately)

[Killerjunior]

@Killerjunior has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would love to work on this.

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

[wandooadzer-cmyk]

@wandooadzer-cmyk has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Can i work on this task?

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