Add format customization and step-based progress display to Bar

[Copilot]

Plan to Add Step-Based Progress Format Support

• Modify Bar constructor to accept optional format parameters
• Add current and total placeholders to the display() method
• Ensure backward compatibility (default behavior unchanged)
• Create tests to validate the new functionality
• Run existing tests to ensure no regressions
• Validate the changes with a manual test script
• Fix code style issues (trailing whitespace)
• Add example demonstrating the new functionality
• Run code review
• Run full test suite
• Fix off-by-one errors in example loops
• Add current, total, and percent placeholders to formatTiming and format

Original prompt

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This section details on the original issue you should resolve

<issue_title>Cannot display step-based progress with format alone</issue_title>
<issue_description>## The Problem
Sometimes, it could be necessary to display not the percentage of the progress, but how many steps are completed out of a total. For example, something like this:

5/10 [==============================>                              ] 0:00 / 0:00

Instead of something like this:

50% [==============================>                              ] 0:00 / 0:00

Currently, this is not possible without overriding the Bar class.

Possible Cause

1. The constructor of Bar, declared in Progress, does not accept a format parameter.
2. The placeholders passed to Streams::render() do not include the _current and _total values.

Suggested Solution

1. Accept a format argument in the constructor.
2. Pass the necessary values of the respective members for _current and _total.

Remarks

What about other formats, like timing? Should they also be accepted as parameters?

Comments on the Issue (you are @copilot in this section)

@danielbachhuber > * Accept a format argument in the constructor. > > * Pass the necessary values of the respective members for `_current` and `_total`.

This seems reasonable. Want to put together a pull request for it?</comment_new>
<comment_new>@danielbachhuber

should we accept an argument for all of the formats? Because there are more.

I think we should only start with those that we need. We can always iterate later.</comment_new>
<comment_new>@schlessera
I actually think it would make more sense to not add to the number of arguments, but just provide a different implementation in your own code if you have special needs. I don't see anything inherently wrong with replacing the Bar class with your own StepBasedBar implementation.

Is there a specific reason why you would want to avoid that?</comment_new>

• Fixes Cannot display step-based progress with format alone wp-cli#5125

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 13 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
lib/cli/progress/Bar.php	0.00%	13 Missing ⚠️

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