chore: add lottie generation script

[United600]

• Moves the AnimatedPlayingVisualSource.json Lottie file from the main project to the repository's assets folder
• Moves the generated AnimatedPlayingVisualSource.cs file from "Controls" to the "Assets" folder
• Updates the xamlstyler.console tool and adds LottieGen to dotnet-tools.json
• Adds a new PowerShell script generate-lottie.ps1 to generate C# animated visuals from JSON files automatically
• Regenerates the animated visual code using the latest LottieGen version

[Copilot]

Pull request overview

This PR improves the developer workflow by adding automation for Lottie animation generation and reorganizes asset files for better maintainability. The changes move Lottie-related files from the main project directory to a dedicated assets folder and introduce a PowerShell script to regenerate animated visual code automatically.

Changes:

• Adds automation script generate-lottie.ps1 to generate C# code from Lottie JSON files
• Updates developer tooling by upgrading xamlstyler.console to version 3.2501.8 and adding LottieGen version 8.2.250604
• Reorganizes files by moving the Lottie JSON source from Controls/Animations/ to assets/animations/ and the generated C# file to Assets/Animations/

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
scripts/generate-lottie.ps1	New PowerShell automation script that processes JSON files from assets/animations and generates C# animated visual classes
assets/animations/AnimatedPlayingVisualSource.json	Lottie animation source file moved from Controls to repository assets folder
.config/dotnet-tools.json	Updates xamlstyler.console to 3.2501.8 and adds LottieGen 8.2.250604 as a dotnet tool
Screenbox/Screenbox.csproj	Updates project to reference the generated file in its new location (Assets/Animations)
Screenbox/Controls/MediaListViewItem.xaml	Updates namespace reference from Screenbox.Controls.Animations to Screenbox.Animations
Screenbox/Assets/Animations/AnimatedPlayingVisualSource.cs	Regenerated C# code with updated namespace, newer LottieGen version, and minor formatting changes