chore: subtree-merge STLShopBook mdbook source (history preserved)

The ShopBook manual source (src/, book.toml, 23 commits of history) now
lives under shop-manual-src/. Content migration to Grav pages follows.

https://projects.knownelement.com/issues/928
This commit is contained in:
2026-09-07 11:26:22 -05:00
47 changed files with 309 additions and 0 deletions
Binary file not shown.

After

Width:  |  Height:  |  Size: 133 KiB