feat: add preferences store with cookie source and output directory

Co-authored-by: Cursor <cursoragent@cursor.com>

src/App.svelte

@@ -6,17 +6,29 @@
   import ClipList from '$lib/components/ClipList.svelte';
   import StatusBar from '$lib/components/StatusBar.svelte';
   import SetupWizard from '$lib/components/SetupWizard.svelte';
+  import PreferencesPanel from '$lib/components/PreferencesPanel.svelte';
+  import { loadPreferences } from '$lib/stores/preferences.svelte';
 
   let showSetupWizard = $state(true);
+  let showPreferences = $state(false);
+
+  $effect(() => {
+    loadPreferences();
+  });
 </script>
 
 {#if showSetupWizard}
   <SetupWizard onComplete={() => (showSetupWizard = false)} />
 {/if}
 
+{#if showPreferences}
+  <PreferencesPanel onClose={() => (showPreferences = false)} />
+{/if}
+
 <div class="app-shell">
   <header class="toolbar">
     <UrlInput />
+    <button class="prefs-btn" onclick={() => (showPreferences = true)} title="Preferences">⚙</button>
   </header>
 
   <main class="content">
@@ -51,4 +63,9 @@
     flex-direction: column;
     overflow: hidden;
   }
+
+  .prefs-btn {
+    font-size: 18px;
+    padding: 4px 8px;
+  }
 </style>