feat(wear): use appLabel placeholder for launcher label

Dev profiles (name ends in -dev) get 'Doctate (Dev)' in the launcher;
production profiles keep the plain 'Doctate'. The string resource
@string/app_name is no longer the application-level label, only used
for the complication entry where the launcher distinction is irrelevant.

refs #3

clients/wearos/app/src/main/AndroidManifest.xml

@@ -15,7 +15,7 @@
         android:name=".DoctateApp"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
-        android:label="@string/app_name"
+        android:label="${appLabel}"
         android:networkSecurityConfig="@xml/network_security_config"
         android:supportsRtl="true"
         android:theme="@android:style/Theme.DeviceDefault">