Add IntegrationTest category and test:integration/test:unit scripts

Co-authored-by: imnasnainaec <6411521+imnasnainaec@users.noreply.github.com>

Author: Copilot

Backend.Tests/Repositories/WordRepositoryTests.cs

@@ -14,6 +14,7 @@ namespace Backend.Tests.Repositories
     /// Integration tests for <see cref="WordRepository"/> that spin up an actual MongoDB instance.
     /// </summary>
     [TestFixture]
+    [Category("IntegrationTest")]
     public sealed class WordRepositoryTests
     {
         private static MongoDbTestRunner _runner = null!;

package.json

@@ -32,6 +32,8 @@
     "test": "run-s test-backend test-frontend",
     "test-backend": "         dotnet test Backend.Tests/Backend.Tests.csproj",
     "test-backend:coverage": "dotnet test Backend.Tests/Backend.Tests.csproj /p:CollectCoverage=true /p:CoverletOutputFormat=lcov /p:Threshold=77",
+    "test:integration": "dotnet test Backend.Tests/Backend.Tests.csproj --filter \"TestCategory=IntegrationTest\"",
+    "test:unit": "dotnet test Backend.Tests/Backend.Tests.csproj --filter \"TestCategory!=IntegrationTest\"",
     "test-frontend": "         node               scripts/jestTest.js",
     "test-frontend:coverage": "node               scripts/jestTest.js --coverage --watchAll=false",
     "test-frontend:debug": "   node --inspect-brk scripts/jestTest.js --runInBand --no-cache",