Create end-to-end test for project token purchase flow

[Josue19-08]

➡️ Title

Create end-to-end test for project token purchase flow

📘 Description

Develop end-to-end tests to validate the full project token purchase flow.

🚀 Requirements

• Test project creation with Soroban contract deployment via POST /projects.
• Test user token purchase via POST /buy-token.
• Verify database entries for projects and purchases.
• Validate correct interaction with Soroban contract functions.

📝 Implementation notes

• Use existing test framework (e.g. Jest, Supertest).
• Mock external dependencies if needed for stable testing.
• Ensure tests cover both success and failure scenarios.

✅ Acceptance Criteria

• End-to-end tests created and passing.
• Covers project creation, contract deployment, token purchase, and database registration.
• Uses kebab-case for all file and folder names.
• Does not use default alias imports or relative paths.
• Uses alias paths with @.
• Code structured with reusable components and reuses existing ones.

⚠ Use kebab-case for all file and folder names.
⚠ Do not use default alias imports or relative paths like ../../components/foo.
⚠ Use alias paths with @, e.g. @/components/foo.
⚠ Structure the code with reusable components and reuse existing ones.