Walks priv/templates/mob.new/android/**/*.eex (resolved from mob_new
— see MobDev.Adopt.Generator), renders each with the project's
assigns, and writes them via Igniter.create_new_file/4 with
on_exists: :skip. Then copies the binary static tree
(priv/static/mob.new/android/**) via direct File.copy!/2 since
Igniter's Rewrite engine assumes UTF-8 text and would corrupt the
Gradle wrapper jar and PNG icons.
Idempotent — on_exists: :skip for EEx-rendered files; File.exists?
pre-check for binaries.
The gradlew script is chmod 0o755 after copy so it's executable.