Full rearchitecture using Claude

- event bus systen
- all components are independent
- preparation for web frontend

python-backend/scenarios/playlist_end.txt

@@ -0,0 +1,19 @@
+# Reaching the end of a playlist stops playback and runs the off animation.
+# eule has two tracks of 5s each.
+
+place eule
+expect playing true
+
+wait 11s
+expect playing false
+expect ring EffectReverseSwipe
+expect brightness 0.00
+
+# the figure is still on the reader, but nothing is playing
+expect figure eule
+
+# taking it off and putting it back starts from the top again
+remove
+place eule
+expect playing true
+expect track 0