Add Stellar network selection helper based on environment configuration

[Cjay-Cyber-2]

Description

Create a centralized helper function to return the correct Stellar Network instance (Testnet vs. Public) based on environment variables.

Context & Requirements

Stellar SDK requires specifying the network passphrase (Test SDF Network ; September 2015 or public network passphrase). Centralizing this configuration prevents inconsistent network usage between signing helpers, horizon queries, and transaction verification.

Acceptance Criteria

• Create or update a Stellar network configuration helper in src/services/ or src/lib/.
• Read network configuration from validated environment variables.
• Export a reusable network instance/passphrase constant for use across Stellar service modules.

Implementation Guidance

• Likely files to touch: src/services/stellar.ts or similar core Stellar utility file.
• Use @stellar/stellar-sdk network classes.

Testing & Validation

• Run npm test to verify that existing Stellar-related tests pass successfully.

Submission Guidelines

• Open a Pull Request referencing Closes #<issue-number>.
• Adhere to TypeScript strict rules and existing codebase formatting standards.

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Wave complexity: Trivial

[aigbagbobila]

@aigbagbobila has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer Can I resolve this kindly assign

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

[DooseWayo]

@DooseWayo has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Can I work on this task?

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

[drips-wave]

Congratulations, @DooseWayo! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @DooseWayo: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

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