Upgrades to Pipelines Artifacts: New Artifact Types & Selective Download

Introduced new artifact types: 'shared' for cross-step data sharing and 'scoped' for step-specific files (logs, reports, screenshots). Implemented selective artifact download, allowing users to specify which artifacts to download in a step (`download: true`, `download: false`, or a list of artifact names). Added `capture-on: failed` for scoped artifacts. Enhanced artifact organization by allowing multiple glob patterns per artifact and specifying ignore patterns and search depth. Updated self-hosted runner version requirement to v3.31.0.