Add social preview image and update meta tags

- Added chiptune_blog_piece_1000x.webp as OpenGraph preview image
- Updated meta tags to point to webp file
- Social sharing on Telegram/Twitter will now show the retro gaming preview

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

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

index.html

@@ -8,7 +8,7 @@
     <!-- OpenGraph / Social Media Preview -->
     <meta property="og:title" content="MOTIF - Procedural Music Synthesis">
     <meta property="og:description" content="Transform MIDI into retro game console vibes. Search, preview, and generate entirely new variations.">
-    <meta property="og:image" content="/og-image.jpg">
+    <meta property="og:image" content="/chiptune_blog_piece_1000x.webp">
     <meta property="og:image:width" content="1200">
     <meta property="og:image:height" content="630">
     <meta property="og:type" content="website">
@@ -18,7 +18,7 @@
     <meta name="twitter:card" content="summary_large_image">
     <meta name="twitter:title" content="MOTIF - Procedural Music Synthesis">
     <meta name="twitter:description" content="Transform MIDI into retro game console vibes. Search, preview, and generate entirely new variations.">
-    <meta name="twitter:image" content="/og-image.jpg">
+    <meta name="twitter:image" content="/chiptune_blog_piece_1000x.webp">
 
     <!-- General Meta -->
     <meta name="description" content="Transform MIDI files into retro synthesized variations. Search for songs, preview them, and generate new procedural versions with retro game console vibes.">