[project42-platform] Publish provider practice curricula

[hcs-platform-app]

Projected from ADO Feature #5441 (Project 42). This issue is bot-managed — edits here are not reflected back to ADO and will be reverted.

Learners need meaningful hands-on Anthropic, OpenAI, and Google practice while retaining portable mental models.

Why now: Project 42 must become a substantial learning product rather than a thin demonstration catalog.

In scope:

• Versioned structured curriculum and resources.
• Learning objectives, lessons, exercises, assessments, sources, and instructor-ready scripts.
• Accessible rendering and provider-neutral editorial review.
• Implementation and release evidence in ADO.

Out of scope:

• The virtual instructor runtime.
• Unreviewed AI-generated factual publication.