Write a guide in a {{tone}} tone for {{target_audience}} covering MVVM implementation at {{complexity}} complexity using {{example_feature}} for the walkthrough. Include these sections: Pattern Overview, Implementation Architecture, Real-World Example, Testing, Common Mistakes (7 items), and Performance Considerations. Keep under 1800 words. Use precise terminology specific to Jetpack Compose. Skip any section if information is unknown. Paste any relevant background information after these instructions before running.