A rune may take editorial runes as a narrative field

Context

The rune authoring guide's "Content boundaries" section (site/content/extend/rune-authoring/patterns.md) says a rune's content model includes exactly what it reinterprets. Content that would render the same inside or outside the rune belongs on the page. It gives three tests:

1. Does the rune give this content new meaning?
2. Does it map to a structured-data field?
3. Is the rune still portable without it?

For recipe, it puts "story, editorial, famous quotes" outside. A recipe is a semantic island in surrounding page prose.

Composition changes the premise of test 1. When a rune's layout was fixed rune CSS, prose inside it could only be appended, so including it bought coupling and nothing else. A composition's template is a layout language. Prose inside the rune can be placed between its parts, which prose outside it can never be. The common food-blog layout cannot be built today:

• the recipe's name, image and times on top;
• the story;
• a card with the ingredients and method.

The top belongs to the recipe, so the story has to sit between two parts of the rune.

Two constraints still hold, and one is new:

• The grammar would collide. Inside {% recipe %}, a list is ingredients, an ordered list is steps and a blockquote is a tip. A story that contains a list of grandma's favourite markets would have them read as ingredients. Loose prose cannot simply be allowed.
• Structured data (test 2). Unmapped visible content breaks neither schema.org nor search guidelines, as long as the published Recipe describes only the recipe.
• Portability (test 3). A recipe embedded elsewhere carries whatever it contains. Today nothing embeds a recipe: @refrakt-md/learning registers no entities, and only plan entities provide sourceFile + extract. The question becomes real once a composed rune can be embedded.