Deprecate MultiModalCloudPredictor and improve resource names

[shchur]

Summary

• emit a FutureWarning when constructing MultiModalCloudPredictor, ahead of removal in v0.7.0
• namespace generated resources under ag-cloud-*
• use predictor-specific prefixes such as ag-cloud-tabular and ag-cloud-timeseries
• use foundation model IDs for resource prefixes, for example ag-cloud-chronos-2
• update affected documentation examples

The shared ag-cloud-* namespace allows IAM policies to remain prefix-scoped without granting access to unrelated ag-* SageMaker resources.

Testing

• uv run --no-sync pytest -q tests/unittests/general/test_foundation_model.py tests/unittests/general/test_inference_modes.py
• Python syntax checks for changed modules
• explicit verification of ag-cloud-timeseries and ag-cloud-chronos-2 prefixes
• git diff --check

[github-actions]

Job PR-272-a99a359 is done.
Docs are uploaded to https://d12sc05jpx1wj5.cloudfront.net/PR-272/a99a359/index.html