Add tests for tensorboard and wandb

[diyasrivas]

Disclaimer

• I am an AI agent.
• I have used AI and I thoroughly reviewed every line.
• I have not used AI extensively.

Description

Note

tldr:
Adds unit tests for the logger field on TrainingConfig and NGTrainingConfig, and also tests for TensorBoard and WandB logger initialisation in CAREamistV2.

Background - why do we need this PR?

WandB and TensorBoard logging in CAREamics currently lacks tests. The existing tests/utils/test_wandb.py was outdated and commented out, having not been updated for the Lightning-based API. As a result, there's no verification for the logging.

Overview - what changed?

1. A new test file covering the logger on both TrainingConfig (old CAREamist) and NGTrainingConfig (CAREamistV2).

2.New tests added to the existing tests/test_careamist_v2_train.py, checking that each logger backend is correctly set up through to the Lightning Trainer and that training completes successfully with each.

I also added interoperability pytest mark in the pyproject.toml.

Implementation - how did you implement the changes?

For tests/config/test_training_config.py: Pydantic's Literal["wandb", "tensorboard"] | None enforces valid values at assignment time; tests exercise this directly via ValidationError assertions

For tests/test_careamist_v2_train.py:

• Each test runs a minimal 1-epoch N2V training pass on a small random array and inspects careamist.trainer.loggers
• WandB disabled-mode test sets WANDB_MODE=disabled so the test runs without a WandB account, making it safe to run in any environment
• Live WandB test is skipped automatically if WANDB_API_KEY is not set; when credentials are present, it verifies that metrics are actually logged to a real WandB run, using a dedicated test project

Changes Made

New features or files

• tests/config/test_training_config.py: 19 tests for the logger field on TrainingConfig and NGTrainingConfig

Modified features or files

• tests/test_careamist_v2_train.py: 4 tests for TensorBoard and WandB logger initialisation and training
• pyproject.toml: interoperability mark added to [tool.pytest.ini_options]

Removed features or files

• removed tests/utils/test_wandb.py

How has this been tested?

All tests ran locally and passed.

Related Issues

Closes #537

Breaking changes

None

Additional Notes and Examples

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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)
• Documentation has been updated
• Pre-commit passes