[9-71]

Overview

Add the Studio runtime layer on top of the merged Core Task Engine (#310).

• Introduce JobsManager as the single owner of public job lifecycle decisions.
• Add bounded CPU/GPU scheduling, cancellation, timeout handling, and process-tree cleanup.
• Implement atomic JSON persistence, backup recovery, and restart reconciliation.
• Provide sanitized job logs, detached status snapshots, and manifest-based artifact access.
• Preserve worker ownership and execution slots until cleanup is confirmed.
• Handle persistence and result-finalization failures without publishing misleading states.

Validation

• Windows Studio tests: 295 passed, 16 skipped (platform-specific).
• WSL2 targeted regression: 64 passed, 0 skipped.
• Additional Windows persistence regression: 49 passed, 2 skipped.
• Doctest: 4 passed.
• Targeted Ruff, format, and codespell checks passed.
• Local lifecycle and failure-path verification completed.

Related to #299.

[isLinXu]

LGTM