Link README to developer Wiki

[MikeChristensen]

Summary

• replace the four historical blog-post links with the current developer Wiki
• add a guided set of links for contexts, recipes, NLP, shopping lists, PostgreSQL provisioning, and ASP.NET Core
• point the capability-profile section to its expanded Wiki page

Validation

• published and checked all linked Wiki pages first
• verified there are no missing internal Wiki page targets
• compiled representative documentation examples against the current Core and DB projects
• ran