feat: add Meta CAPI + Google Enhanced Conversions server-side tracking

- Add /api/conversions endpoint (Meta CAPI + GA4 Measurement Protocol)
- SHA-256 PII hashing, event_id deduplication, fbp/fbc cookies
- Client-side sendConversion() utility in PageShell.astro
- Lead event tracking on form submit in home.js
- GA4 allow_enhanced_conversions config

src/components/PageShell.astro

@@ -78,16 +78,18 @@ const organizationJsonLd = JSON.stringify({
     <!-- ConsentOS (cookie consent — load first) -->
     <script src="https://consent.moreminimore.com/consent-loader.js" data-site-id="2f6d0ab5-f7d6-4d06-b299-5069c21f6238" data-api-base="https://consent.moreminimore.com"></script>
 
-    <!-- Google Analytics 4 -->
+    <!-- Google Analytics 4 + Enhanced Conversions -->
     <script is:inline async src="https://www.googletagmanager.com/gtag/js?id=G-74BHREDLC3"></script>
     <script is:inline>
       window.dataLayer = window.dataLayer || [];
       function gtag(){dataLayer.push(arguments);}
       gtag('js', new Date());
-      gtag('config', 'G-74BHREDLC3');
+      gtag('config', 'G-74BHREDLC3', {
+        allow_enhanced_conversions: true
+      });
     </script>
 
-    <!-- Meta Pixel -->
+    <!-- Meta Pixel + event_id support -->
     <script is:inline>
       !function(f,b,e,v,n,t,s)
       {if(f.fbq)return;n=f.fbq=function(){n.callMethod?
@@ -98,7 +100,57 @@ const organizationJsonLd = JSON.stringify({
       s.parentNode.insertBefore(t,s)}(window, document,'script',
       'https://connect.facebook.net/en_US/fbevents.js');
       fbq('init', '418349260078648');
-      fbq('track', 'PageView');
+      
+      // Generate event_id for PageView deduplication
+      var pvEventId = 'pv_' + Date.now() + '_' + Math.random().toString(36).substr(2,9);
+      fbq('track', 'PageView', {}, {eventID: pvEventId});
+    </script>
+
+    <!-- Conversion Tracking Utilities -->
+    <script is:inline>
+      window.generateEventId = function(prefix) {
+        return (prefix || 'evt') + '_' + Date.now() + '_' +
+               Math.random().toString(36).substr(2,9) +
+               Math.random().toString(36).substr(2,9);
+      };
+
+      window.getMetaCookies = function() {
+        var c = document.cookie.split(';').reduce(function(a,x) {
+          var p = x.trim().split('=');
+          a[p[0]] = p[1]; return a;
+        }, {});
+        return { fbp: c._fbp || null, fbc: c._fbc || null };
+      };
+
+      window.sendConversion = function(eventName, eventData, userInfo) {
+        var eventId = window.generateEventId(eventName.toLowerCase());
+        var mc = window.getMetaCookies();
+
+        // Client-side fire
+        if (window.fbq) fbq('track', eventName, eventData || {}, {eventID: eventId});
+        if (window.gtag) gtag('event', eventName, eventData || {});
+
+        // Server-side: Meta CAPI + Google EC
+        fetch('/api/conversions', {
+          method: 'POST',
+          headers: {'Content-Type': 'application/json'},
+          body: JSON.stringify({
+            event_name: eventName,
+            event_id: eventId,
+            event_time: Math.floor(Date.now() / 1000),
+            event_source_url: window.location.href,
+            user_data: {
+              em: userInfo?.email || null,
+              ph: userInfo?.phone || null,
+              fn: userInfo?.firstName || null,
+              ln: userInfo?.lastName || null,
+              fbp: mc.fbp,
+              fbc: mc.fbc
+            },
+            custom_data: eventData || {}
+          })
+        }).catch(function(e) { console.error('[CAPI]', e); });
+      };
     </script>
 
     <!-- Umami Analytics -->