chore: Fix .gitignore - remove test file exclusions, add coverage folder

- Removed incorrect exclusion of *.test.ts and *.test.js files
- Added coverage/ folder to .gitignore
- Removed accidentally committed coverage files

Co-authored-by: mindesbunister <32161838+mindesbunister@users.noreply.github.com>

.gitignore

@@ -31,12 +31,6 @@ logs/
 # Docker
 .dockerignore
 
-# Test files
-*.test.ts
-*.test.js
-test-*.ts
-test-*.js
-
 # Temporary files
 tmp/
 temp/
@@ -45,3 +39,6 @@ temp/
 # Build artifacts
 dist/
 .backtester/
+
+# Coverage reports
+coverage/