/**
 * Heuristic token estimation.
 *
 * Average English text is roughly 4 characters per token.
 * Code and structured content (JSON, XML) tend toward 3 characters per token
 * because of short identifiers, brackets, and punctuation.
 *
 * This estimator detects structural content and smoothly interpolates between
 * 4 (pure prose) and 3 (dense code/JSON) based on the ratio of structural
 * characters. It intentionally leans toward slight over-estimation so the
 * budget is never accidentally exceeded.
 */
export declare function estimateTokens(text: string): number;