Add StopPredictionCallback to lightning callbacks

[diyasrivas]

Description

Note

tldr: AddedStopPredictionCallback to CAREamics lightning callbacks for prediction stopping.

Overview - what changed?

This PR moves the prediction stopping functionality from careamics-napari to the main CAREamics library. The callback now accepts a generic Callable[[], bool] condition instead of UI-specific state objects.

Changes Made

New features or files

• StopPredictionCallback class in src/careamics/lightning/callbacks/stop_prediction_callback.py
• PredictionStoppedException exception for signaling prediction interruption
• Test in tests/lightning/callbacks/test_stop_prediction_callback.py

Modified features or files

• src/careamics/lightning/callbacks/__init__.py - added new exports
• src/careamics/lightning/__init__.py - exposed the callback

How has this been tested?

• All tests pass (pytest tests/lightning/callbacks/ -v)
• New test covers callback initialization, stopping behavior, and stateful conditions
• Verified imports work correctly: from careamics.lightning.callbacks import StopPredictionCallback, PredictionStoppedException

Related Issues

• Resolves Next-Gen CAREamics: move stop prediction callback from caremics-ui to careamics #746

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Please ensure your PR meets the following requirements:

• Code builds and passes tests locally, including doctests
• New tests have been added (for bug fixes/features)
• Pre-commit passes
• PR to the documentation exists (for bug fixes / features)

[diyasrivas]

I tried to make a test tests/lightning/callbacks/test_stop_prediction_callback.py but I am not as experienced with this.. if you think it is unnecessary I can remove it.

[jdeschamps]

All good, but indeed most tests need to go away. I made commit suggestions, you can just commit them if you agree.