Update .gitignore and enhance test documentation for coverage reporting

- Add /bench/backups, /target/, cobertura.xml, and tarpaulin-report.html to .gitignore to prevent tracking of generated files.
- Update test.md to include instructions for running tests and generating coverage reports using cargo tarpaulin.

.gitignore

@@ -45,3 +45,6 @@ saved_config.yaml
 # === Other Dirs ===
 /bench/corpus
 /bench/backups
+/target/
+/cobertura.xml
+/tarpaulin-report.html

cli-bin/tests/test.md

@@ -70,3 +70,9 @@ or
 ```bash
 ./run_all_tests.sh
 ```
+
+to see test coverage run:
+
+```bash
+cargo tarpaulin --out Html
+```