feat(ui): unify themes and harden app flows - #13

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262, actions/setup-java@cf277c60eb25467037889841efdb72551f06f6c3, actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02, android-actions/setup-android@9fc6c4e9069bf8d3d10b2204b1fb8f6ef7065407, gradle/actions/setup-gradle@0b6dd653ba04f4f93bf581ec31e66cbd7dcb644d. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/