This is the initial release. My Apple Developer Account is brand-new, and I haven't yet finished working my way through Apple contractural stuff related to this enough that I have been able to notarize this release. Drag-and-drop, settings (for AWS details), notifications when long-running uploads complete and a "nice-enough" (I'm no designer) UI complete this version enough that it'll meet my needs.
Full Changelog: https://github.com/joshmcarthur/droplet/commits/v1