Reads the release keystore from env vars in CI, falling back to the
debug keys locally. Adds fastlane metadata for F-Droid/Obtainium and
a .forgejo workflow that builds, signs, and publishes the APK on
pushing a vX.Y.Z+N tag.
Without an adaptive icon or a v31 splash theme, Android synthesized a
white circular backdrop and shrank the flat square logo to fit inside
it, both on the home screen and the native splash screen. Add a real
adaptive icon (background color plus a centered, safe-zone-scaled
vector foreground from the same path data as assets/logo.svg) and
configure the v31 splash screen to use matching background colors, so
the logo fills the shape edge to edge instead.
