* Reject unknown recipe variant keys * Deslop recipe.ts JSDoc and tighten predeclared-config wording Say why RejectUnknownKeys exists once, at its own type, instead of repeating the reasoning on SinglePartConfig, MultiPartConfig, and withDefaultVariants. Spell out "a config declared before the recipe() call" instead of "predeclared config" in recipe.ts, recipe.test.ts, and STYLING.md, and split the test file's header comment into one sentence per idea.