/**
 * Detect BPM from audio.
 *
 * Input contract (explicit — no silent guessing):
 *   - An AudioBuffer (channel 0 and its sampleRate are read), or
 *   - A Float32Array of raw mono PCM, in which case `options.sampleRate`
 *     (a positive number) is REQUIRED.
 * Anything else throws a TypeError with a clear diagnostic. A genuine
 * detection failure on valid audio (no steady pulse found) resolves to
 * { bpm: null, confidence: 0, error } rather than a fabricated tempo.
 *
 * @param {AudioBuffer|Float32Array} input - Audio to analyze
 * @param {Object} [options] - Detection options (sampleRate required for Float32Array)
 * @returns {Promise<Object>} BPM result
 */
export function detectBPM(input: AudioBuffer | Float32Array, options?: any): Promise<any>;