src/lib/storage.ts

```typescript
import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3"
import { v4 as uuidv4 } from "uuid"

const s3Client = new S3Client({
  endpoint: process.env.S3_ENDPOINT,
  region: process.env.S3_REGION,
  credentials: {
    accessKeyId: process.env.S3_ACCESS_KEY,
    secretAccessKey: process.env.S3_SECRET_KEY,
  },
})

export async function uploadFile(file: File) {
  const fileKey = `tracks/${uuidv4()}${file.name}`
  await s3Client.send(
    new PutObjectCommand({
      Bucket: process.env.S3_BUCKET_NAME,
      Key: fileKey,
      Body: Buffer.from(await file.arrayBuffer()),
    })
  )
  return fileKey
}
```