Added loading 5et from zip release, or cloning git repo. Improvements to CSS and some missing functionality

README.md

@@ -8,8 +8,15 @@ Current stage:
 ## Prerequisites
 
 - Node.js 20+
-- `5etools-src` directory in this repository root:
-  - `./5etools-src`
+- Git (only required if setup mode uses source/image repository URLs)
+
+On first launch, if no local source is found, the app opens a setup window.
+Setup supports either:
+
+- Source repository URL clone
+- Local source ZIP import
+
+Images can be cloned from an image repository URL, and/or loaded from an external image base URL fallback.
 
 Optional override: