Implement @stellar-pay/sdk-js base client class

[MissBlue00]

Task

Create the StellarPay client class as documented in the README at packages/sdk-js/README.md.

Details

• Add StellarPay class with constructor accepting { apiKey, webhookSecret } config
• Implement createPayment(params) method that POSTs to the API
• Implement verifyWebhook(signature, body) that validates HMAC-SHA256 signatures
• Implement listPayments(filters) method
• Export StellarPay as default from src/index.ts

Path

• packages/sdk-js/src/index.ts

Test

Run pnpm --filter @stellar-pay/sdk-js build to verify no TypeScript errors.

[Achievers-sketch]

@Achievers-sketch has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I can implement the StellarPay SDK client with payment creation, payment listing, HMAC-SHA256 webhook verification, proper exports, and TypeScript-safe builds.

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

[omosvico]

@omosvico has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi can I be assigned to this issue?

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

[Agencybuilds]

@Agencybuilds has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

i would love the opportunity to work on this issue, i'm motivated . detail oriented , and ready to contribute a solid solution while helping the community grow.

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