add arch tech doc

README.md

@@ -4,6 +4,11 @@ English README. Swedish version: [`README.sv.md`](README.sv.md)
 
 JMK RB RaceController is an RC timing and race-control system with support for sponsor events with shared cars/transponders, AMMC WebSocket input, and local persistence through SQLite.
 
+## Architecture
+
+- JavaScript module overview: `docs/javascript-architecture.md`
+- Swedish operational guide: `README.sv.md`
+
 ## Screenshots
 
 ### Overview