v0.15.0

• Added. Contract::validateWebhook(string $name, RequestInterface $request, ?ResponseInterface $response = null) validates an incoming
  webhook delivery against the OpenAPI 3.1 webhooks map (#158). Each
  entry compiles to one Operation per method, a Path Item without a
  path: no template, no path parameters (in: path is refused), no server
  matching — the delivery's URL is the receiver's own. Parameters in the
  query, header and cookie, the request body and, when a response is
  passed, the receiver's answer go through the ordinary pipeline; an
  undeclared name or method is one request.operation.unknown violation.
  Contract::webhooks() lists them by name; operations() and match()
  keep to path operations; operation() and validateResponse() answer a
  webhook's key — its operationId, else WEBHOOK <METHOD> <name>.
  Operation gains a defaulted webhook parameter (append-only: named
  arguments) carrying the map key, and violations point under
  /webhooks/<name>. A 3.1 document declaring only webhooks loads; the
  refusal now applies to a document with neither paths nor webhooks
  operations, and a 3.0 document carrying webhooks is refused as such.
• Changed. A body that fails its schema is reported per leaf failure
  (#160): each request.body.schema / response.body.schema violation
  names the failing member in instancePath ($.age,
  $.children[2].name), the assertion in the new Violation::$keyword
  (minimum, type, required, ...; null on every other violation),
  and carries that one assertion as expected — {"minimum": 0} rather
  than the media type's schema. A required member the value lacks is
  reported at the path it would have had with null as actual; the
  list is bounded at twenty leaves; a leaf two union branches report
  alike is reported once; a failure of the value itself keeps $. The
  codes are unchanged — this is a diagnostic change — but a consumer that
  asserted exactly one body violation, or instancePath === '$', now
  sees more. ValidationResultFormatter prints a keyword line where
  one is set and renders a body member's actual as it renders a
  parameter's — the credential name pattern applies to the member path
  and to the names inside it, so $.age prints -1 and $.password
  prints [redacted]; a whole-body violation at $ stays redacted
  wholesale.
• Changed. For a oneOf/anyOf that declares a discriminator, the
  body diagnostics follow the branch the propertyName value names —
  through mapping, as a $ref or a component name, else by the
  component name the value spells — instead of reporting every branch's
  errors; a value naming no branch is one violation at the discriminator
  member with the keyword discriminator. The verdict is untouched: every
  branch is still evaluated. So that a branch keeps its name, a $ref
  branch of a discriminated union is now compiled as the local
  {$ref: '#/$defs/…'} a shared component takes rather than inlined; a
  consumer that read such a branch's members off Operation follows the
  reference into the schema's $defs, as it already does for a cycle.