feat: add phone/LINE click conversion tracking (gtag + Meta Pixel)

- New component: ContactEventTracker.astro
- Fires phone_click/line_click events via gtag (Google Ads)
- Fires PhoneClick/LineClick custom events via fbq (Meta Pixel)
- Throttled 500ms, bot-filtered, pathname-tagged
- Wired into BaseLayout.astro (all pages)

src/layouts/BaseLayout.astro

@@ -2,6 +2,7 @@
 import '@/styles/global.css';
 import Layout from './Layout.astro';
 import JsonLd from '@/components/seo/JsonLd.astro';
+import ContactEventTracker from '@/components/tracking/ContactEventTracker.astro';
 
 const companyInfo = {
   name: "ดีล พลัส เทค จำกัด",
@@ -910,4 +911,7 @@ const productLinks = [
       }
     });
   </script>
+
+  <!-- Contact Event Tracker (Phone + LINE clicks) -->
+  <ContactEventTracker />
 </Layout>