feat(kon): add first-run hardware probe and model recommendation wizard

- New probe_system command: returns RAM, CPU, OS info
- New rank_models command: scores models against detected hardware
- FirstRunPage.svelte: hardware summary, ranked model list with
  "Recommended" badge on top pick, download progress bar, skip option
- First-run detection in layout: checks list_models + list_parakeet_models,
  shows wizard if both empty
- Sidebar hidden during first-run for clean wizard experience
- clippy clean

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/routes/+page.svelte

@@ -5,6 +5,7 @@
   import TasksPage from "$lib/pages/TasksPage.svelte";
   import HistoryPage from "$lib/pages/HistoryPage.svelte";
   import SettingsPage from "$lib/pages/SettingsPage.svelte";
+  import FirstRunPage from "$lib/pages/FirstRunPage.svelte";
 
   // Redirect legacy "profiles" page to settings
   $effect(() => {
@@ -13,7 +14,9 @@
 </script>
 
 <div class="h-full overflow-hidden">
-  {#if page.current === "dictation"}
+  {#if page.current === "first-run"}
+    <FirstRunPage />
+  {:else if page.current === "dictation"}
     <DictationPage />
   {:else if page.current === "files"}
     <FilesPage />