v0.8.0

• Understudy::for() no longer kills the process on five built-in
  interfaces. Throwable, UnitEnum, BackedEnum, DateTimeInterface and
  Traversable walked past every refusal in the factory and were answered by
  the compiler instead — a fatal out of eval(), uncatchable by try or by an
  adapter, and fatal to the whole suite run rather than to one test. Each is now
  an UnsupportedTarget naming the way through. Iterator,
  IteratorAggregate, Stringable and Countable keep doubling: it was never
  about being built in.
• A duplicated contract is accepted rather than fatal.
  Understudy::for(A::class, A::class) — a list assembled programmatically —
  produced the same uncatchable fatal, because implements A, A does not
  compile.
• #[\SensitiveParameter] is honoured. The value of such a parameter is
  rendered as its type — login('user', string SensitiveParameter) — in
  failure messages and in transcript(), the way PHP redacts it in its own
  stack traces. It used to go into both verbatim, which is to say into a CI log.
• Three public paths now throw an UnderstudyError. times(5, 2), a
  negative count and returns() with no values threw a bare
  \InvalidArgumentException, while UnderstudyError declares itself
  implemented by every exception this library throws — so a catch (UnderstudyError $e), which llms.txt recommends, walked past them. The new
  InvalidSpecificationArgument extends \InvalidArgumentException, so a catch
  by the SPL type keeps working.
• Arg::instanceOf() refuses a class that is not loadable. It used to
  match nothing, forever, and say so nowhere — the reader saw only "expected …
  but it was never called" and looked for the cause in the subject under test.
• NAN no longer raises a PHP warning while a failure message is rendered.
  On PHP 8.5 (string) NAN warns, from inside the library, during the render of
  a report about a failure — which under failOnWarning turns the report into a
  different failure.
• Control bytes and binary strings are escaped in messages. A NUL or half a
  broken UTF-8 sequence travelled into the failure text and the transcript as
  the raw byte, breaking the single line the escaping exists to keep. Valid
  multibyte text is untouched.
• CannotWire and InvalidDefaultValue say "has type array" and "produced a
  value of type array" instead of "is a array".
• Documentation: checkpoint() clears only the settled calls, not the call
  log (the text promised otherwise, and the code was right); a declared property
  default is kept while a promoted one is not; a built-in interface as a return
  type does not become a nested double; Arg::string() uses PCRE semantics for
  $; both Security sections say that arguments are printed verbatim except
  sensitive ones. A broken cookbook link in examples/README.md and a dead plan
  reference in docs.yml are gone, and the committed API pages are regenerated
  from the current src/ (they were built from a v0.5.0 snapshot).