feat: add complete OG and Twitter Card meta tags

- Add og:url, og:image with absolute URL to generated OG card
- Add og:image:width, og:image:height, og:image:type dimensions
- Add og:image:alt for accessibility
- Add Twitter Card meta tags (summary_large_image)
- Point to generated 1200x630 PNG at /img/og-card.png

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: MaxDaten

src/templates/template.html

@@ -12,12 +12,22 @@
         <meta name="date" content="$date-meta$" />
         $endif$
         <meta name="description" content="$if(subtitle)$$subtitle$ - $endif$Curriculum Vitae of $pagetitle$" />
+        <!-- Open Graph Meta Tags -->
         <meta property="og:title" content="$pagetitle$$if(subtitle)$ - $subtitle$$endif$" />
         <meta property="og:type" content="profile" />
         <meta property="og:description" content="$if(subtitle)$$subtitle$ - $endif$Curriculum Vitae" />
-        $if(profile-picture)$
-        <meta property="og:image" content="$profile-picture$" />
-        $endif$
+        <meta property="og:url" content="https://cv.maxdaten.io/" />
+        <meta property="og:image" content="https://cv.maxdaten.io/img/og-card.png" />
+        <meta property="og:image:width" content="1200" />
+        <meta property="og:image:height" content="630" />
+        <meta property="og:image:type" content="image/png" />
+        <meta property="og:image:alt" content="$pagetitle$ - $if(subtitle)$$subtitle$$endif$" />
+        <!-- Twitter Card Meta Tags -->
+        <meta name="twitter:card" content="summary_large_image" />
+        <meta name="twitter:title" content="$pagetitle$$if(subtitle)$ - $subtitle$$endif$" />
+        <meta name="twitter:description" content="$if(subtitle)$$subtitle$ - $endif$Curriculum Vitae" />
+        <meta name="twitter:image" content="https://cv.maxdaten.io/img/og-card.png" />
+        <meta name="twitter:image:alt" content="$pagetitle$ - $if(subtitle)$$subtitle$$endif$" />
         <title>$if(title-prefix)$$title-prefix$ - $endif$$pagetitle$</title>
         <style type="text/css">
             code {