chore: improve .gitignore to exclude generated files

- Exclude generated Power Query files (*_PowerQuery.m)
- Exclude backup files (*.backup.*)
- Exclude debug extraction and sync folders
- Better organization for maintainability

Author: Wilson421

.gitignore

@@ -3,4 +3,24 @@ dist
 node_modules
 .vscode-test/
 *.vsix
-test/*
+test/out/
+test/.vscode-test/
+
+# Generated Power Query files (extracted from Excel)
+*_PowerQuery.m
+
+# Testing folder with large files and sensitive data
+temp-testing/
+
+# Test backup files
+*.backup.*
+test/**/*.backup.*
+test/fixtures/*.backup.*
+
+# Debug extraction folders
+*_debug_extraction/
+test/fixtures/*_debug_extraction/
+
+# Debug sync folders
+debug_sync/
+test/fixtures/debug_sync/