Add an OpenSubsonic-compatible API - #220

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-dotnet@v4, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

P/Invoke method 'Open16' should not be visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1401)

P/Invoke method 'Open' should not be visible (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1401)

'RNGCryptoServiceProvider' is obsolete: 'RNGCryptoServiceProvider is obsolete. To generate a random number, use one of the RandomNumberGenerator static methods instead.' (https://aka.ms/dotnet-warnings/SYSLIB0023)

'RNGCryptoServiceProvider' is obsolete: 'RNGCryptoServiceProvider is obsolete. To generate a random number, use one of the RandomNumberGenerator static methods instead.' (https://aka.ms/dotnet-warnings/SYSLIB0023)

'Rfc2898DeriveBytes.Rfc2898DeriveBytes(string, byte[], int)' is obsolete: 'The constructors on Rfc2898DeriveBytes are obsolete. Use the static Pbkdf2 method instead.' (https://aka.ms/dotnet-warnings/SYSLIB0060)

'Thread.VolatileWrite(ref int, int)' is obsolete: 'Thread.VolatileRead and Thread.VolatileWrite are obsolete. Use Volatile.Read or Volatile.Write respectively instead.' (https://aka.ms/dotnet-warnings/SYSLIB0054)

'SHA1CryptoServiceProvider' is obsolete: 'Derived cryptographic types are obsolete. Use the Create method on the base type instead.' (https://aka.ms/dotnet-warnings/SYSLIB0021)

'SHA1CryptoServiceProvider' is obsolete: 'Derived cryptographic types are obsolete. Use the Create method on the base type instead.' (https://aka.ms/dotnet-warnings/SYSLIB0021)

'MD5CryptoServiceProvider' is obsolete: 'Derived cryptographic types are obsolete. Use the Create method on the base type instead.' (https://aka.ms/dotnet-warnings/SYSLIB0021)