[Project 42] Improve the public story and learning/reference experience

[hcs-platform-app]

Projected from ADO Feature #5765 (Project 42). This issue is bot-managed — edits here are not reflected back to ADO and will be reverted.

The three-site release is a strong foundation, but the landing page does not yet fully explain why the product is called Project 42 or establish a repeatable way to improve the Learn and Field Guide experiences.

Why now: The owner considers the current release a good start and wants the product story, learning content, and practical reference content to keep becoming more useful.

In scope:

• Explain the Project 42 name and its connection to curiosity, the famous science-fiction answer of 42, and the need for a well-planned AI learning and reference system.
• Improve how the landing page routes newcomers and experienced practitioners to Learn and Field Guide.
• Audit and prioritize improvements to learning content and the learning journey.
• Improve Field Guide quality and discovery while coordinating with the legacy-restoration Feature [AB#5728](https://dev.azure.com/hybridcloudsolutions/65db102b-0f2f-439e-af54-1d9db2f3c6ff/_workitems/edit/5728).
• Establish observable quality and feedback signals for future improvements.

Out of scope:

• Changing the accepted three-site repository or hostname boundaries.
• Duplicating the legacy-content inventory already tracked by [AB#5728](https://dev.azure.com/hybridcloudsolutions/65db102b-0f2f-439e-af54-1d9db2f3c6ff/_workitems/edit/5728).
• Implementing authentication, durable learner records, or the virtual-instructor runtime.
• Using copyrighted film artwork, dialogue, or branding.