feat(output): add progress bar context manager to Output class

[ChristopherJHart]

The Output class currently supports status messages, success/warning/error output, and logging, but lacks progress bar support for long-running operations like device connections and test execution.

Requirements

• Add Output.progress(description: str, total: int) -> ProgressContext method
• Return a context manager that wraps Rich's progress bar functionality
• Support incrementing progress (advance()) and updating description
• Degrade gracefully when stdout is not a TTY (plain text updates)

Use cases

• "Connecting to devices [████████────] 8/10"
• "Running tests [██████████████──] 45/50"
• Phase execution progress within the runner

References

docs/08-output-logging-design.md — "Output Class Interface" and "Console Output" sections.