improved component composition and added tests.

src/routes/Compose.svelte

@@ -1,7 +1,6 @@
 <script lang="ts">
   /** A full-page composer, reachable from the nav and from "Send Message". */
-  import { session } from '$lib/stores/session.svelte'
-  import { router } from '$lib/router.svelte'
+  import { useAppServices } from '$lib/app-services'
   import Module from '$components/common/Module.svelte'
   import Composer from '$components/blog/Composer.svelte'
 
@@ -12,6 +11,7 @@
 
   let { to }: Props = $props()
 
+  const { router, session } = useAppServices()
   const prefill = $derived(to ? `@${to.replace(/^@/, '')} ` : '')
 </script>
 
@@ -26,12 +26,15 @@
 
   <div class="layout--single">
     <Module title={to ? 'New message' : 'New entry'}>
-      <Composer
-        initialText={prefill}
-        placeholder={to ? 'Say something…' : 'What are you up to?'}
-        submitLabel={to ? 'Send' : 'Post Entry'}
-        onposted={(status) => router.go(`#/blog/${status.id}`)}
-      />
+      {#key to}
+        <Composer
+          initialText={prefill}
+          initialVisibility={to ? 'direct' : 'public'}
+          placeholder={to ? 'Say something…' : 'What are you up to?'}
+          submitLabel={to ? 'Send' : 'Post Entry'}
+          onposted={(status) => router.go(`#/blog/${status.id}`)}
+        />
+      {/key}
     </Module>
 
     {#if !session.signedIn}