feat: implement audio waveform visualization in SampleCard

[brightpixel-dev]

Overview

The SampleCard currently shows static decorative waveform bars. We should replace these with a real animated waveform visualization that reflects the actual audio data from the IPFS-stored beat.

Acceptance Criteria

• Fetch waveform peak data from audio file (or generate via Web Audio API)
• Animate bars on hover / during preview playback
• Fallback to static bars if audio analysis fails
• No noticeable performance impact on the marketplace grid (60fps)

Implementation Notes

Consider using wavesurfer.js or a lightweight custom Web Audio API canvas renderer. The waveform data could be pre-generated at upload time and stored as IPFS metadata.

Related: feat/audio-preview branch

[barry01-hash]

My chief, i will love to work on this issue