task(lint): enable ThrowIf* analyzers (CA1510–CA1513) #539

Description

Enable the following .NET code-quality analyzers, which modernize argument/state guard
clauses to the concise ThrowIf* helpers introduced in .NET 8:

• CA1510 —
  Use ArgumentNullException.ThrowIfNull instead of if (x is null) throw new ArgumentNullException(...).
• CA1511 —
  Use ArgumentException.ThrowIfNullOrEmpty instead of if (string.IsNullOrEmpty(x)) throw new ArgumentException(...).
• CA1512 —
  Use ArgumentOutOfRangeException.ThrowIf* (e.g. ThrowIfNegative, ThrowIfGreaterThan) instead of
  if (x < 0) throw new ArgumentOutOfRangeException(...).
• CA1513 —
  Use ObjectDisposedException.ThrowIf instead of if (disposed) throw new ObjectDisposedException(...).

Enabling them only requires setting their severity in .editorconfig:

# CA1510: Use ArgumentNullException.ThrowIfNull
dotnet_diagnostic.CA1510.severity = error
# CA1511: Use ArgumentException.ThrowIfNullOrEmpty
dotnet_diagnostic.CA1511.severity = error
# CA1512: Use ArgumentOutOfRangeException.ThrowIf*
dotnet_diagnostic.CA1512.severity = error
# CA1513: Use ObjectDisposedException.ThrowIf
dotnet_diagnostic.CA1513.severity = error

Checklist

• Add the four dotnet_diagnostic.CA151{0,1,2,3}.severity = error entries to .editorconfig.
• Replace existing guard clauses with the corresponding ThrowIf* helpers.
• Confirm the Lint build is green.