chore(release): Floatick 0.3.1

[lucaslus]

Summary

• improve the mobile 3D showcase by removing the backdrop on compact screens
• make compact settings descriptions readable across two lines
• bump the app and website release metadata to 0.3.1+8

Verification

• dart format --output=none --set-exit-if-changed lib test integration_test
• flutter analyze
• flutter test
• npm run build (website)
• flutter build macos --release --build-name 0.3.1 --build-number 8
• candidate workflow, architecture verification, smoke test, SHA256, and manifest validation