[9-71]

Overview

Add the Studio Core Task Engine for YOLO-Master, providing a unified, synchronous execution layer for train, val, predict, export, and diagnose.

• Task schema and validation, dispatcher, handler registry, and task handlers.
• Fail-closed path whitelist checks for traversal, symlink escapes, broken symlinks, and malformed regex rules.
• Credential sanitization for logs and errors.
• Forward validated training imgsz to model.train().
• Reuse the upstream trainer's optimizer-group audit.

This PR focuses on the Core execution layer.

Validation

• Ubuntu Studio Core CI: 183 passed, 0 skipped.
• Windows Studio Core CI: passed.
• Doctest: 4 passed.
• Ruff, format, and codespell: passed.
• Real-model predict / tiny train / export: 3 passed.
• Manual predict + tiny train smoke tests: 2 passed.

Related to #299

[isLinXu]

LGTM