Refine ASR progress bar presentation

[morehardy]

Summary

• Replace thick/block window progress with a thin full-length progress track
• Show percentage and elapsed time instead of window counts
• Keep TTY Rich rendering and non-TTY fallback aligned

Review

• Checked TTY/non-TTY behavior, file completion, and progress cleanup paths
• No blocking issues found in the changed console observer code

Test Plan

• PYTHONPATH=src uv run --frozen --python 3.14 python -m unittest discover -s tests -p 'test_*.py'

[gemini-code-assist]

Code Review

This pull request updates the console progress display by introducing a thin progress bar style, switching from raw counts to percentages, and improving time formatting. Feedback suggests that the manual newline handling in _stop_progress and the associated _stream_ends_with_newline helper are likely redundant and inefficient, as the Rich library typically manages terminal cleanup and getvalue() is not suitable for standard output streams.

[gemini-code-assist]

The manual newline appended here appears redundant when using rich.progress.Progress with transient=False (the default in _ensure_progress), as Rich typically appends a newline when the live display stops. The current check _stream_ends_with_newline only works for streams that implement getvalue() (like io.StringIO used in tests) and will always return False for standard streams like sys.stdout. This will likely result in an extra blank line in real terminal output between files or steps. Consider removing this manual newline and relying on Rich's built-in cleanup.

            self._last_width = 0

[gemini-code-assist]

Using getvalue() on the stream to check for a trailing newline is inefficient for large streams, as it copies the entire buffer into memory. While this is primarily used in tests, it's a fragile pattern for a general-purpose observer. If the manual newline in _stop_progress is removed as suggested, this helper method would no longer be necessary.

[morehardy]

Addressed Gemini review feedback in 8335300:

• Removed the manual newline write from _stop_progress().
• Removed _stream_ends_with_newline() and its getvalue()-based stream inspection.
• Kept _last_width reset after Rich progress stops.

Verification:

• PYTHONPATH=src uv run --frozen --python 3.14 python -m unittest discover -s tests -p "test_*.py"
• GitHub Unit tests are passing.