Remove newtonsoft, make the library native aot compatible

[idan-h]

Chore

Describe the chore

Bring supabase-csharp (and the sub-packages we use) up to .NET Native AOT so a dotnet publish -c Release -p:PublishAot=true build succeeds, and there are no runtime errors.

Acceptance criteria

• AOT publish finishes without linker errors or reflection warnings.
• App boots and runs basic Supabase flows (auth, simple CRUD) in the published binary.
• CI job produces an AOT artifact.

Steps

1. Add a repo-level Directory.Build.props with:

   <Project>
     <PropertyGroup>
       <PublishAot>true</PublishAot>
       <PublishTrimmed>true</PublishTrimmed>
       <InvariantGlobalization>true</InvariantGlobalization>
       <EnableDynamicLoading>false</EnableDynamicLoading>
     </PropertyGroup>
   </Project>

2. Swap Newtonsoft.Json for System.Text.Json + source-generated context.

3. Mark BaseModel with DynamicallyAccessedMembers and tag helper methods that use reflection with RequiresUnreferencedCode.

4. Replace Activator.CreateInstance calls with new T().

5. Run:

   dotnet restore
   dotnet build -c Release
   dotnet publish -c Release -p\:PublishAot=true -p\:SelfContained=true -o ./aot
   

   Fix any remaining trim warnings.

6. Update CI pipeline to run the publish step and cache the output.

Additional context

Reference the detailed checklist in docs/aot-supabase-notes.md.

[EricRichterAtAmcopia]

Also, I would like to suggest to

• remove the 'new()' requirement in the 'where' statements of TModel to allow using the 'required' keyword in model class definitions like

[Table("my_table")]
  public class MyTable : BaseModel
  {
      [PrimaryKey("id")]
      [Column("id")]
      public Guid Id { get; init; }

      [Column("category")]
      public required string Category { get; init; }

      [Column("display_name")]
      public required string DisplayName { get; init; }

      [Column("description")]
      public string? Description { get; init; }
  }

This would reduce errors when creating new model instances.

• remove the requirement that model classes need to derive from 'BaseModel'. All methods of 'BaseModel' can be provided e.g. as extension methods with the required parameters as method parameters ('BaseUrl' and so on). By this, model class definitions would become leaner.