v0.1.0

• Initial release: schema-as-code combinators with three ports wired to one
  definition — parse() (runtime validation with structured error paths,
  rendered as $.tags[2] and RFC 6901 /tags/2), arbitrary()
  (a rasuvaeff/property-testing-core generator over the exact same value
  set) and toJsonSchema() (a pure draft 2020-12 fragment through
  JsonSchemaExport). The parity between the ports is the package's law,
  pinned by its own property suite over random schema trees: generated
  values parse (source domain), and their wire projection validates against
  the export through opis (wire domain).
• Types: string (code-point length bounds, full-match pattern, named
  formats email/uuid/uri/date-time/ipv4), int (bounds), bool,
  literal, enum (backed; accepts an instance or the backed value,
  returns the instance), json (the json_decode domain), arrayOf
  (list, count bounds), mapOf (string keys, count bounds), object
  (required/optional/default properties, additionalProperties), union
  (first success wins), nullable, lazy (recursive shapes, factory
  memoized).
• Combinators: transform (target-space generation, source-space shrinking,
  optional inverse for round-trip laws, optional wire PHP→JSON converter
  and jsonSchema codec — strict export throws without a codec, the
  declared codec is checked against the generator's actual output),
  refine (post-condition; filtered generation; exports as an honest
  superset plus a NonRepresentable entry).
• Object semantics: an absent optional key is absent from the result (not
  null); default() implies optional(), is validated against the schema
  at construction and stored normalized (an enum default may be given as
  its backed value). The default JSON Schema annotation goes through the
  wire seam. Error messages never embed input values — kinds and sizes
  only.
• regex() accepts the Gen::stringMatching convention (no delimiters)
  and eagerly probes generatability: a pattern the generator cannot
  compile is an authoring error at construction, not an explosion in
  arbitrary().