TermKit 0.2.1: curation integrity and Studio hierarchy

[ZilaiWang]

What changed

• completes the Draft Inbox and atomic ChangeSet lifecycle
• adds CJK-aware runtime boundaries and a real compiled runtime backend
• splits workspace responsibilities into repository, service, and unit-of-work layers
• adds derived concept projections, recovery mode, and durable canonical-write recovery
• delivers Concepts 2.0, semantic review, navigation hierarchy, semantic UI families, and refreshed documentation/screenshots
• adds component, API, workflow, Playwright E2E, and visual regression coverage

Why

TermKit backend capabilities needed a complete and legible curation workflow. This release closes the path from local edits through review and canonical apply, while making runtime behavior and crash recovery explicit and testable.

Validation

• Ruff and Mypy passed
• 61 Python tests passed; coverage 85.64%
• 7 Vitest tests passed
• 2 Playwright E2E/visual tests passed
• schema, architecture, embedded Studio asset, frontend production build, wheel and sdist checks passed