Add Test Coverage for plugin-rabbi-trader Package

[ai16z-demirix]

Is your feature request related to a problem? Please describe.

The plugin-rabbi-trader package lacks comprehensive test coverage, making it difficult to ensure reliability and catch potential issues during development. Without proper tests, we risk introducing bugs when making changes and have no automated way to verify core functionality like wallet operations, DEX interactions, and token utilities.

Describe the solution you'd like

Implement comprehensive test coverage for the plugin-rabbi-trader package using vitest. The solution includes:

Test Infrastructure Setup:

• Configure vitest with appropriate settings
• Add test dependencies and scripts to package.json
• Set up proper mocking utilities
  Core Component Tests:
• Wallet functionality (keypair generation, balance checking)
• DexScreener integration (data fetching, pair analysis)
• Token utilities (address loading, validation)
  Test Coverage Requirements:
• Success and error cases for each component
• Edge case handling
• Proper mocking of external dependencies

Describe alternatives you've considered

1. Using Jest instead of vitest, but vitest provides better performance and ESM support
2. End-to-end testing with real network calls, but this would make tests slower and less reliable
3. Snapshot testing for complex objects, but unit tests provide better specificity and error messages

Additional context

[ai16z-demirix]

Done.