Unmodifiable view of the constraint metadata recorded via addCheck.
Empty for schemas built without constraints, or for constraints not yet
annotated (which simply don't appear in the exported schema).
Non-allocating raw lists. Library-internal use only — never expose
these to consumers because they bypass the unmodifiable contract.
Used by specialized schema implementations (ZInt, ZDouble, etc.) to
avoid creating an List.unmodifiable wrapper per parse() call.
Records introspectable metadata about a constraint as it is applied, so
the schema can be exported to JSON Schema / OpenAPI without executing
it. Builder methods (.min/.max/.email/.regex/...) call this
alongside addValidator. By convention check is the target JSON Schema
keyword (e.g. 'minLength', 'pattern', 'format') and value its
value, so a converter can map an entry to node[check] = value directly.
Attaches a human-readable description to this schema, emitted into the
exported JSON Schema / OpenAPI. Purely documentational — it does not
affect validation. Chainable; call it after constraints:
z.string().min(1).describe('Full name').
Internal entry point used by container schemas (ZMap, ZList, ZUnion,
ZInterface, etc.) to avoid the per-field/per-item try/catch overhead
of public parse. On success returns the parsed value and leaves
sink unchanged. On failure appends at least one issue to sink
(callers determine success by comparing sink.length before/after).
