Implement Account Offers Retrieval Tool

[adams813]

Description:
Add get_account_offers to list active DEX orders for a specific account.

Rules:

• Use existing standards and modules within the backend architecture.
• Ensure strict adherence to Stellar/Soroban best practices.
• Maintain high security standards and data privacy.

Guidelines:

• Integrate seamlessly with existing Pulsar toolsets.
• Follow the DRY (Don't Repeat Yourself) principle.
• Provide comprehensive error handling and diagnostic information.

Acceptance Criteria:

• Feature implemented and verified via unit/integration tests.
• Documentation updated to reflect changes.
• Performance impact within acceptable limits.

Definition of Done:

• Code reviewed and merged.
• 100% test coverage for new logic.
• AI-ready tool schema or contract spec available.

[Chigybillionz]

@Chigybillionz has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hello,
I would like to contribute to this issue and resolve it.

I will send my PR today
Thank you.

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

[MickeeJay]

@MickeeJay has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hello Maintainer,
I’ve carefully read the issue and understand what’s needed. I’ll implement this in a way that maintains consistency with the current architecture.

Ready to proceed once assigned.

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