Feature/indeterminate progress with elapsed

[IAdityaKaushal]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

This PR adds support for indeterminate progress bars that show elapsed time and expected total, addressing issue #3572. Linked here #3572

Problem

Users requested a way to display progress bars in an indeterminate state (animated pulse) while still showing elapsed time and an indicator like ?/total. Currently, using start=False or total=None either doesn't show elapsed time or doesn't allow for the desired display format.

Solution

• Added indeterminate and expected_total parameters to tasks
• Created new rendering logic for indeterminate progress bars with animated pulsing effect
• Added IndeterminateTaskProgressColumn to display ?/total for indeterminate tasks
• Preserved elapsed time display during indeterminate state
• Enabled smooth transition from indeterminate to determinate state

Features Added

• Indeterminate progress bars show animated pulse with elapsed time
• Tasks can be created with indeterminate=True and optional expected_total
• New IndeterminateTaskProgressColumn displays ?/total for indeterminate tasks
• Seamless transition from indeterminate to determinate (green 100%) completion
• Comprehensive test coverage for new functionality

Example Usage

with Progress() as progress:
    # Create an indeterminate task with expected total
    task_id = progress.add_task(
        "Indexing",
        indeterminate=True,
        expected_total=10
    )
    
    # Later, convert to determinate
    progress.update(
        task_id,
        indeterminate=False,
        total=10,
        completed=10
    )

[willmcgugan]

There is way too much going on in this PR. There seems to be code unrelated to progress bars.

At this point, I can't accept new features. Especially if those features could be implemented outside of the core library.