Create a single-file browser-native audio workstation benchmark with 16-step sequencing, synth controls, modulation, live controls, and tactile UI.

Route brief followed:

- Build one self-contained HTML artifact for `/audio-lab/`.
- Use a browser-native Web Audio engine with explicit user interaction to unlock sound.
- Provide a 16-step sequencer with transport, tempo, swing, pattern editing, mute/solo basics, and visible playhead state.
- Include multiple sound voices: kick, snare, hi-hat, bass synth, chord stab, and arpeggio pluck.
- Add synth controls for filter cutoff, resonance, envelope, delay send, drive, and LFO modulation.
- Persist pattern and control state locally with save/recall/reset actions.
- Design the UI as a tactile groovebox: large pads, knobs, status meters, waveform/scope feedback, and touch-friendly controls.