Fix Windows test deadlock by removing aggressive defer cleanup

[geofffranks]

The previous defer cleanup logic was causing test deadlocks on Windows:

• defer functions were checking session.ExitCode() == -1 and calling Kill()
• This interfered with natural process termination via session.Terminate()
• Tests failed with "Expected process to exit. It did not."

Solution:

• Remove aggressive defer cleanup from individual test cases
• Rely on AfterEach cleanup for port management
• Let processes exit naturally without interference
• Keep cross-platform signal handling (Windows: 42, Unix: 143)

This allows Windows tests to pass while maintaining proper cleanup through the existing AfterEach hook and Serial execution.

Made-with: Cursor

• Read the Contributing document.

Summary

Backward Compatibility

Breaking Change? Yes/No