A scaffold is the package handing a consumer code it wrote itself, so a stub the package's own
judge then flags is the worst kind of finding: the consumer did not write it, cannot be taught
by it, and learns to ignore the checklist. Two were doing exactly that.

- HiddenAwareAttributedClassTransformer's docblock carried a second paragraph of registration
  prose (BloatedDocblock); it is one tight paragraph now, instruction intact.
- SwitchCase.vue tripped ControlFlowOnElement on its own `<slot v-if>` / `<slot v-else>` — the
  irreducible core of the very construct that FIXES that sin. A `<slot>` is a compile-time
  outlet that renders no element of its own, so there is no content for the structure to be
  mixed with; it is exempt alongside `<template>`, which the rule has always spared.

A new test judges every stub with the whole catalogue, both engines, so this cannot recur.

Closes #388