I'm a product design student. I'm not familiar with the terminal or writing code. Please build this for me with HTML, CSS, JavaScript and native Web Audio. Make a simple, usable browser page, with no external libraries or internet services. Sound should start only after I click. Use comfortable initial levels. I need to play with the result, not read code. Extend the loops-and-events app with an audio file picker. Show the imported file name and duration before it plays. Let me choose Loop or Event and its level. Use the existing event timing and stop rules. Start with MP3 and WAV. Show a useful error for an unsupported or damaged file. For now imports last only until reload: say this clearly. Choosing a file must not start it automatically. I want to try a sound I generated myself.