scripts/fdroid-publish.sh builds a signed arm64 APK and adds it to an
F-Droid repo in a given directory, creating the app signing key and the
repo on first use. The versionCode is the commit count, so any commit can
ship without a manual version bump.
Release builds are signed when src-tauri/gen/android/keystore.properties
exists and stay unsigned otherwise. The manifest picks up the deep-link
plugin's intent filter, which every build regenerates and was never
committed.