/**
 * Preserves `${VAR}` environment variable references during config write-back.
 *
 * When config is read, `${VAR}` references are resolved to their values.
 * When writing back, callers pass the resolved config. This module detects
 * values that match what a `${VAR}` reference would resolve to and restores
 * the original reference, so env var references survive config round-trips.
 *
 * A value is restored only if:
 * 1. The pre-substitution value contained a `${VAR}` pattern
 * 2. Resolving that pattern with current env vars produces the incoming value
 *
 * If a caller intentionally set a new value (different from what the env var
 * resolves to), the new value is kept as-is.
 */
/**
 * Deep-walk the incoming config and restore `${VAR}` references from the
 * pre-substitution parsed config wherever the resolved value matches.
 *
 * @param incoming - The resolved config about to be written
 * @param parsed - The pre-substitution parsed config (from the current file on disk)
 * @param env - Environment variables for verification
 * @returns A new config object with env var references restored where appropriate
 */
export declare function restoreEnvVarRefs(incoming: unknown, parsed: unknown, env?: NodeJS.ProcessEnv): unknown;