feat(analytics): add optional Aptabase event tracking UI

Integrate Aptabase analytics via a Tauri plugin and add a privacy
notice flow plus a settings dialog to control whether anonymous
usage events are sent. The app now tracks key user actions while
ensuring analytics never blocks core Git operations.

- Add analytics tracking helper and Aptabase plugin wiring
- Persist analytics consent in localStorage and gate tracking
- Introduce notice and settings dialogs, plus new event calls

src/lib/components/AnalyticsNoticeDialog.svelte

@@ -0,0 +1,57 @@
+<script lang="ts">
+  import { BarChart3, Check, ShieldCheck } from "@lucide/svelte";
+
+  interface Props {
+    enabled: boolean;
+    onContinue: (enabled: boolean) => void;
+  }
+
+  let { enabled = true, onContinue = () => {} }: Props = $props();
+  let allowAnalytics = $state(true);
+
+  $effect(() => {
+    allowAnalytics = enabled;
+  });
+</script>
+
+<div class="dialog-backdrop app-chrome-backdrop" role="presentation">
+  <div class="dialog analytics-notice-dialog" role="dialog" aria-modal="true" aria-label="Analytics notice" tabindex="-1">
+    <header class="dialog-header">
+      <div>
+        <span class="eyebrow">Privacy</span>
+        <h2 class="dialog-title">Anonymous usage analytics</h2>
+      </div>
+      <ShieldCheck size={20} aria-hidden="true" />
+    </header>
+
+    <div class="analytics-notice-body">
+      <div class="analytics-notice-icon">
+        <BarChart3 size={24} aria-hidden="true" />
+      </div>
+      <div class="analytics-notice-copy">
+        <p>
+          GitLite can send anonymous usage events to Aptabase so crashes, rough edges, and commonly used workflows are easier to improve.
+        </p>
+        <p>
+          Events do not include repository paths, remote URLs, branch names, commit messages, diffs, file names, credentials, or source code.
+        </p>
+      </div>
+
+      <label class="settings-toggle-row analytics-notice-toggle">
+        <input type="checkbox" bind:checked={allowAnalytics} />
+        <span>
+          <strong>Allow anonymous analytics</strong>
+          <small>You can change this later in Settings.</small>
+        </span>
+      </label>
+    </div>
+
+    <footer class="dialog-footer analytics-notice-footer">
+      <span class="dialog-footer-info">Privacy-friendly, optional, and limited to product usage events.</span>
+      <button class="btn-primary" type="button" onclick={() => onContinue(allowAnalytics)}>
+        <Check size={16} aria-hidden="true" />
+        Continue
+      </button>
+    </footer>
+  </div>
+</div>