Bug fixes with on-disk result storage

[ben-nowacki]

Description

Fixes with on-disk result storage

• On-disk storage failed to save callback results. Evaluation callback results were overwritten for multi-epoch training phases.
• Created new CallbackStore to follow ArtifactStore, MetricStore, and ExecutionStore pattern
• On-disk pickle files now use global, monotonically increasing file names to prevent naming collisions
• Experiment serialization updated to support this logic

Fixed no-length progress tasks not refreshing

• New manual-refresh approach to ProgressManager failed to refresh no-length ProgressStyles (e.g., ProgressSpinner)
• Added new auto-refresh task with ProgressStyle instances allowed to opt-in to this refresh thread

Related Issues

N/A

How Has This Been Tested?

• Local pytest run
• CI passes
• Manual checks (describe if needed)

Checklist

• My code follows project style guidelines: nox -s pre-commit
• I have added tests that prove my fix is effective or my feature works: nox -s unit
• I have updated documentation if needed: nox -s docs
• I have linked related issues

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 17.85714% with 115 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...odularml/core/experiment/results/callback_store.py	37.77%	28 Missing ⚠️
modularml/utils/progress_bars/progress_manager.py	10.71%	25 Missing ⚠️
modularml/core/io/handlers/experiment_handler.py	0.00%	19 Missing ⚠️
...odularml/core/experiment/results/artifact_store.py	5.26%	18 Missing ⚠️
modularml/core/experiment/experiment.py	0.00%	8 Missing ⚠️
modularml/core/experiment/results/metric_store.py	0.00%	5 Missing ⚠️
...odularml/core/experiment/results/results_config.py	16.66%	5 Missing ⚠️
modularml/core/experiment/results/phase_results.py	33.33%	4 Missing ⚠️
...dularml/core/experiment/results/execution_store.py	0.00%	3 Missing ⚠️

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