Add Comprehensive Test Suite

[tufo830]

The project currently has zero test coverage, which poses significant risks for maintainability, refactoring safety, and regression detection. A comprehensive test suite is essential for production-grade software.

Current State

• No tests/ directory exists
• No pytest, unittest, or any testing framework configuration
• No CI/CD pipeline for automated testing
• No test coverage reporting
• Only one testing utility found in the verl module (not integrated)

Impact

Without tests:

• Refactoring is dangerous - Changes may introduce silent bugs
• Regressions go undetected - No safety net when adding features
• Documentation gap - Tests serve as executable examples
• Contributor friction - New contributors can't verify their changes
• Production risk - No confidence in deployment stability

[Harvey-zhou]

Yes, as this project is evolving quickly, we don't have test coverage currently. We plan to add comprehensive tests as the architecture stabilizes.