feat: the About dialog pitches the app in two lines

Tagline plus one line of key points in both languages, rendered as a
centred list; the GitHub button points at the real repository.

src/lib/components/AboutDialog.svelte

@@ -1,7 +1,6 @@
 <script lang="ts">
   import { t } from '../i18n/i18n.svelte';
-  // Placeholder until the project's repository is public; swap the URL when known.
-  const REPO_URL = 'https://github.com/your-org/edentext';
+  const REPO_URL = 'https://github.com/stffnb/edentext';
 
   let { open = $bindable(false) }: { open?: boolean } = $props();
 
@@ -47,6 +46,12 @@
 
     <p class="tagline">{t().about.tagline}</p>
 
+    <ul class="points">
+      {#each t().about.points as point}
+        <li>{point}</li>
+      {/each}
+    </ul>
+
     <p class="version">{t().about.version(__APP_VERSION__)}</p>
 
     <a class="repo" href={REPO_URL} target="_blank" rel="noopener">
@@ -148,6 +153,19 @@
     color: var(--color-text-muted);
   }
 
+  .points {
+    margin: 0;
+    padding: 0;
+    list-style: none;
+    text-align: center;
+    font-size: 0.78rem;
+    line-height: 1.5;
+    color: var(--color-text-muted);
+    display: flex;
+    flex-direction: column;
+    gap: 6px;
+  }
+
   .version {
     margin: 0;
     font-size: 0.78rem;

src/lib/i18n/locales/de.ts

@@ -514,7 +514,8 @@ const de: Messages = {
   },
   about: {
     label: 'Über EdenText',
-    tagline: 'Ein privater Editor für OpenDocument-Dateien — läuft vollständig im Browser.',
+    tagline: 'Textverarbeitung — nur eine URL entfernt.',
+    points: ['Free · Open Source · Private by Design'],
     version: (v) => `Version ${v}`,
     viewOnGitHub: 'Auf GitHub ansehen',
   },

src/lib/i18n/locales/en.ts

@@ -520,7 +520,8 @@ const en = {
   },
   about: {
     label: 'About EdenText',
-    tagline: 'A private editor for OpenDocument files — runs entirely in your browser.',
+    tagline: 'Powerful word processor — just one URL away.',
+    points: ['Free · Open Source · Private by Design'],
     version: (v: string) => `Version ${v}`,
     viewOnGitHub: 'View on GitHub',
   },