Brings the v0.3.0 release line into main: Kubernetes backend (k8s / k8s_mpi),
merge-pod same-node GPU fabrics, recursive deep-merge composition, declarative
result parsing + S3 uploads, hardware monitoring, and richer run summaries.

The logging-filter files (logging.py, core/launcher.py, cli/batch.py and their
tests) conflicted because the main-only hotfix (#11: _DropTaskStreamFilter
per-task log routing + venv bootstrap fix) was developed independently on both
branches. Resolved by taking develop's version, which already incorporates that
hotfix as a strict superset (every main-side test also present on develop).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>