separate dev and production instances and add visual indicators of dev mode

src/App.svelte

@@ -14,6 +14,7 @@ import Unlock from './views/Unlock.svelte';
 // set up app state
 invoke('get_config').then(config => $appState.config = config);
 invoke('get_session_status').then(status => $appState.sessionStatus = status);
+invoke('get_devmode').then(dm => $appState.devmode = dm)
 getVersion().then(version => $appState.appVersion = version);
 invoke('get_setup_errors')
     .then(errs => {
@@ -51,7 +52,7 @@ acceptRequest();
 </script>
 
 
-<svelte:window 
+<svelte:window
     on:click={() => invoke('signal_activity')}
     on:keydown={() => invoke('signal_activity')}
 />
@@ -70,3 +71,9 @@ acceptRequest();
     <!-- normal operation -->
     <svelte:component this="{$currentView}" />
 {/if}
+
+{#if $appState.devmode }
+    <div class="fixed left-0 bottom-0 right-0 py-1 bg-warning text-xs text-center text-warning-content">
+        This is a development build of Creddy.
+    </div>
+{/if}