chore: simplify plugin readmes, changelogs and manifest descriptions

plugins/serial/CHANGELOG.md

@@ -2,7 +2,6 @@
 
 ## 1.0.0
 
-Converted from core's `src/backend/hosts/serial.ts` and
-`src/ui/features/serial/` in Termix 2.9.0. Its own port (30011) and nginx
-blocks are gone; it now serves `/plugin-ws/serial/console` like every other
-plugin.
+First release, bundled with Termix 2.9.0.
+
+Opens a serial console to a device plugged into your computer. The desktop app talks to the device directly, and the browser uses Web Serial.