/**
 * Source for the `helpers/json-helpers.ts` file written into generated output.
 *
 * This module used to be a working implementation *and* the generator carried a second,
 * hand-maintained copy of the same code as a template string in
 * `Transformer.ensureJsonHelpersFile`. Only the template shipped; nothing imported this
 * module. Two copies of one program, with nothing keeping them in step.
 *
 * It now follows the pattern `decimal-helpers.ts` already uses: one function returning the
 * source text, called by the writer. The emitted result is type-checked by
 * tests/generated-output-compiles.test.ts, whose fixture schema has a `Json` column, and its
 * behaviour is pinned by tests/emitted-json-helpers.test.ts — so the copy users receive is
 * the copy that is verified.
 *
 * `z` is assumed to be in scope: the caller prepends the zod import, whose binding style
 * depends on zodImportTarget.
 */
export declare function generateJsonHelpers(): string;