Add project documentation and configure for JavaScript/TypeScript

- Add PRD and TSD defining SDK and Explorer architecture
- Add CLAUDE.md with project guidance for Claude Code
- Update README with project description
- Replace Python .gitignore with JS/TS configuration

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -1,3 +1,11 @@
-# repo-seed
+BinectJs
 
-A git repository template to bootstrap coulomb projects from.
+*Javascript Binect API wrapper*
+
+# Binect JS - Send Papermail from your Browser
+
+An easy to use javascript library to send pdf-documents as papermail using the app.binect.de API.
+
+For documentation of the API see: https://app.binect.de/index.jsp?id=api
+
+xxx