docs: publish economics book blueprint

[unityequilibrium]

Summary

• add the actual he_origin_of_wealth_book_blueprint.md file to the public economics book folder
• link the blueprint from the public README and book workspace index
• update the public manifest and work ledger so the boundary is clear

Scope control

This PR publishes one markdown blueprint file only. It does not publish raw folders, chapter draft folders, media, PDFs, audio, or private source dumps.

Test Plan

• git diff --cached --check
• reviewed staged file list: 5 markdown files only
• kept README wording clear that the blueprint is a draft planning artifact, not a validated economics result