Refactor test configurations and enhance testing framework

- Replace TempConfig with DummyConfig across tests for consistency
- Introduce unit tests workflow configuration
- Add pytest configuration for standardized test discovery
- Implement comprehensive tests for config loading and downloader behavior
- Clean up unused temp_config.py and related references

.gitignore

@@ -4,6 +4,7 @@
 #Custom for this project
 config/yt-playlist-config.json
 /tmp*
+*.code-workspace
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]