Enhance traffic generator error handling and logging

[DeVikingMark]

Why are these changes needed?

The traffic generator has several critical issues with error handling and resource management:

• Goroutine errors are silently ignored
• No proper error propagation from worker instances
• Resource leaks in ticker usage
• Insufficient logging for debugging production issues
• Lack of proper shutdown handling

These changes implement proper error handling, improve logging, and fix resource management issues.

Checks

• I've made sure the tests are passing. Note that there might be a few flaky tests, in that case, please comment that they are not relevant.
• I've checked the new test coverage and the coverage percentage didn't drop.
• Testing Strategy
  • Unit tests
  • Integration tests
  • This PR is not tested :(