[split] Refactor / cleanup — from #21

[pull-apart]

Automated split from #21.

Context

This is the refactor / cleanup half of an automated split from #21.

Changes in this PR:

• utilities/unittests/test_console.py: Updated imports to include subprocess, pexpect, and pytest
• Added _single_attempt_sampler helper for simplified TimeoutSampler mocking in tests
• Updated test_console_disconnect_terminated_child to mock _proc status instead of child.terminated
• Updated test_console_eof_sampler_success and test_console_eof_sampler_no_sample to reflect console_eof_sampler parameter changes and internal call to _spawn_console
• Added new test cases for _spawn_console() covering success and failure scenarios
• Added new test cases for _terminate_proc() covering various termination states
• Added new test cases for connect() method, including error handling for TimeoutExpiredError and pexpect exceptions
• Added new test cases for disconnect() method, covering clean exit, EOF, and error conditions

How this split maps your changes

• Refactor branch (split-pr-21-1783426939-refactor): files classified as cleanup / mechanical work:
  • utilities/unittests/test_console.py
• Main branch (split-pr-21-1783426939-main): files classified as feature / behavior work:
  • utilities/console.py

Merge order

Merge the refactor PR first if it touches shared files or would conflict with the main PR; then merge the main PR. Resolve conflicts in the usual way if both branches touch the same lines.

Main PR: #36