Add bottom status memory and traffic metrics

[NghiaTranUIT]

Summary

• Add a lightweight status metrics service for process memory and live captured upload/download speed
• Render the metrics on the right side of the bottom status strip without rebuilding the full packet UI on timer ticks
• Cover byte accumulation, reset behavior, duplicate prevention, direction filtering, and formatter rounding with unit tests

Testing

• Unit tests added for the metrics service and status strip formatting
• Full macOS build and test were run with code signing disabled locally due a missing development certificate in this environment