Improve checks output

[dbrosio3]

This pull request introduces a new planned check display system for deterministic check runs, improving how checks are presented and updated in the terminal, especially for TTY (interactive) streams. The changes add a richer, more dynamic transcript output, clearly showing which checks are running, updating their statuses in-place, and handling scenarios like early termination due to fail-fast. The update also includes expanded test coverage for these behaviors.

The most important changes are:

Transcript and Display Improvements:

• Introduced the DeterministicCheckDisplay and DeterministicTranscriptPlannedCheck interfaces, and updated DeterministicCheckPlanEntry to include a display property, allowing each check to specify its label and details for transcript output. (src/runner/deterministic-plan.ts [1] [2] [3] [4]
• Refactored the transcript system to accept and track a list of planned checks, displaying their initial "running" state and updating each row in-place as results become available, using ANSI cursor control on TTY streams. (src/runner/transcript.ts [1] [2] [3] [4] [5] [6]

Terminal Output Enhancements:

• Added a new "running" status to TerminalStatus, with corresponding symbols and colors for both ASCII and Unicode output, and refactored row formatting to support dynamic updates. (src/terminal/format.ts [1] [2] [3] [4] [5]

Fail-fast and Skipped Checks Handling:

• Implemented logic to mark all remaining planned checks as "skipped" with an appropriate message when a fail-fast condition halts the run, ensuring accurate transcript output. (src/runner/transcript.ts [1] [2]

Testing and Utilities:

• Expanded tests to verify the new transcript behaviors, including TTY row updates and fail-fast skipping, and added utility helpers for simulating TTY streams and environment overrides in tests. (test/deterministic-runner.test.ts [1] [2] [3] [4] [5]

These changes collectively make the check run output clearer, more interactive, and robust in both interactive and non-interactive environments.