dist.sh builds versioned, signed artifacts for both apps from a git tag

(semver drives Android versionCode/versionName and package.json). The
build-image/ Dockerfile pins the same toolchain for a portable,
containerized Gitea Actions runner (build-image.sh builds and pushes
it) so releases don't depend on any one machine's local setup.
Pushing vX.Y.Z now builds and publishes a Gitea Release automatically.

registry.env.example

@@ -0,0 +1,6 @@
+# Copy to registry.env (gitignored, never commit the real values) and fill in.
+# Used by build-image.sh to push the build environment image to cr.ladkau.de.
+REGISTRY=cr.ladkau.de
+REGISTRY_IMAGE=cr.ladkau.de/schwert-und-magie/builder
+REGISTRY_USER=
+REGISTRY_PASSWORD=