Assessing energy impact of PRs

We would ideally like the ability to assess power impact over time using tools like Xcode Instruments and the Android [Power Profiler](https://android-developers.googleblog.com/2024/04/how-to-effectively-ab-test-power-consumption-for-your-android-app-features.html). Unsure if CLI tools exist for either, but opening an issue to track.

Start by investigating Xcode Instruments and the Android Power Profiler, including whether either provides CLI support for assessing power impact over time. Define the supported platforms, measurement workflow, and a reproducible result before implementation; the issue does not name any repository files or tests.

Written by the indexing model from the issue text.