Update to .NET 10 LTS and improve test coverage

Author: ANcpLua

.gitignore

@@ -148,4 +148,16 @@ ehthumbs.db
 TestResult.xml
 nunit-*.xml
 
-ocr/
+ocr/
+
+# Test outputs
+CreatePdf.NET.Tests/output/
+test_output.txt
+build-output.txt
+
+# Coverage results
+coverage-results/
+coverage-check/
+
+# Temporary files
+temp/