The project exposes a large number of implementation types that should be hidden from consumers

[kzu]

• Make Jq.Parse internal
• Change JqFilter to internal abstract class; make CreateNullElementStatic, StructurallyEqual, GetTypeNameStatic, GetValueTextStatic internal
• Change JqParser to internal sealed class
• Change JqHaltException to internal sealed class
• Change JqBreakException to internal sealed class
• Change JqEnvironment to internal sealed class
• Change JqPattern, VariablePattern, ArrayPattern, ObjectPattern to internal
• Change FilterClosure to internal sealed record
• Change BinaryOp to internal enum
• Change UserFunctionDef to internal sealed class
• Change all ~30 filter classes in Filters/ to internal sealed class
• Build and verify

Note that per .editorconfig, redundant visibility should NOT be specified: so internal class should just be class, and private [type] [field] should just be [type] [field].