Rename package com.eddy.atomrelay -> nl.eddydevink.sylda, Dutch translations, UI cleanup

- Package renamed to nl.eddydevink.sylda (matches eddydevink.nl domain + Sylda app name)
- All status texts translated to Dutch (Niet verbonden, Verbonden, Zoeken, etc.)
- Removed exchange key button, build number, and success toasts
- Button text: Firmware bijwerken, instruction text shortened
- App title changed to Sylda, 'instellingen' label next to settings gear
- ON/HOLD changed to AAN/VAST

android/app/build.gradle

@@ -4,14 +4,14 @@ plugins {
 }
 
 android {
-    namespace 'com.eddy.atomrelay'
+    namespace 'nl.eddydevink.sylda'
     // compileSdk/targetSdk stays on 34 (Android 14) by deliberate choice. The target audience
     // consists of physically disabled users who are very reluctant to update their phones. Staying
     // on API 34 maximises device compatibility. Re-evaluate when the user base has migrated.
     compileSdk 34
 
     defaultConfig {
-        applicationId "com.eddy.atomrelay"
+        applicationId "nl.eddydevink.sylda"
         minSdk 26
         targetSdk 34
         versionCode 1