M3 expressive wavy progress indicators

[dfabulich]

This PR upgrades us to androidx-material3 1.5.0-alpha16, so we can access the new M3 Expressive stuff.

I've added a new .material3WavyProgress() modifier. You can pass it no arguments, and it will do the right thing, or you can configure the amplitude, wavelength, and "wave speed"

Skip Pull Request Checklist:

• REQUIRED: I have signed the Contributor Agreement
• REQUIRED: I have tested my change locally with swift test
• OPTIONAL: I have tested my change on an iOS simulator or device
• OPTIONAL: I have tested my change on an Android emulator or device
• REQUIRED: I have checked whether this change requires a corresponding update in the Skip Fuse UI repository (link related PR if applicable)
  No skip-fuse-ui changes required.
• OPTIONAL: I have added an example of any UI changes in the Showcase sample app
  M3 expressive wavy progress indicators skipapp-showcase#85

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• AI was used to generate or assist with generating this PR. Please specify below how you used AI to help you, and what steps you have taken to manually verify the changes.

Cursor generated a first draft, which I manually cleaned up and documented. I manually tested the new progress indicators in the ProgressViewPlayground in both the Lite and Fuse showcases.

Before / After

Screen_recording_20260401_200124.webm