[#79] Entities: Remove EF proxies

Tests/UnitTests/DocumentTests/MemberDataSheetTest.cs

@@ -1,5 +1,4 @@
 using Elwig.Documents;
-using Elwig.Helpers;
 
 namespace Tests.UnitTests.DocumentTests {
     [TestFixture]
@@ -7,9 +6,7 @@ namespace Tests.UnitTests.DocumentTests {
 
         [Test]
         public async Task Test_01_SimpleMember() {
-            using var ctx = new AppDbContext();
-            var m = await ctx.Members.FindAsync(104);
-            using var doc = new MemberDataSheet(m!, ctx);
+            using var doc = await MemberDataSheet.Initialize(104);
             var text = await Utils.GeneratePdfText(doc);
             Assert.Multiple(() => {
                 Assert.That(text, Contains.Substring("""