fix(core): fully-qualify IReportArtifactStore in ReportRunner (CS0246)

CI clean build failed because ReportRunner (namespace NeoReports.Core.Pipeline)
referenced sibling 'Artifacts.IReportArtifactStore' without a using; a stale local
obj masked it. Use the fully-qualified NeoReports.Core.Artifacts.* name. Verified
with obj/bin wiped: clean full build + all 58 tests green.

Author: thiagoluga

src/NeoReports.Core/Pipeline/ReportRunner.cs

@@ -197,7 +197,7 @@ await writer.InitializeAsync(
 
                 // Retain finished files for later retrieval (API download / sync streaming) when an
                 // artifact store is registered. Copying happens before the temp dir is cleaned up.
-                if (services.GetService(typeof(Artifacts.IReportArtifactStore)) is Artifacts.IReportArtifactStore artifactStore)
+                if (services.GetService(typeof(NeoReports.Core.Artifacts.IReportArtifactStore)) is NeoReports.Core.Artifacts.IReportArtifactStore artifactStore)
                 {
                     foreach (var output in outputs)
                         await artifactStore.SaveAsync(