v0.1.0

• Extracted the framework-agnostic engine from rasuvaeff/property-testing
  2.8.1 with FQCNs preserved (namespace Rasuvaeff\PropertyTesting) — a
  drop-in split: generators, integrated shrinking, the property runner,
  the regression corpus, lifecycle events, and stateful/model-based testing.
• Promoted the Runner namespace, the event model (Event\*,
  PropertyListener) and the corpus surface to @api.
• Moved Internal\CorpusStorage to Runner\FilesystemCorpus, and
  CorpusEntry, Clock, MonotonicClock into the Runner namespace.
• Added Gen::subset($values, $minSize, $maxSize) (SubsetArbitrary):
  subsets of a fixed ordered set — duplicates rejected, source order
  preserved, size drawn uniformly, shrinking reduces size first and then
  moves kept elements toward earlier source positions; no discards.
• Declared conflict with rasuvaeff/property-testing (both packages ship
  the Rasuvaeff\PropertyTesting namespace; the frozen 2.x line is
  superseded by this family).