Replace cmd/recipemd and cmd/recipemd-find with a set of simple,
self-contained examples in examples/ that demonstrate library usage:

- examples/parse/    – parse a .md file, output compact JSON (pipe to jq)
- examples/scale/    – scale a recipe by factor or yield, output markdown
- examples/flatten/  – inline linked recipes, output markdown

Also have some minimal tests for the examples to ensure future changes
don't break the examples.