feat: glitter sparkles on heart, metallic gold text across all headings

- Add animated gold sparkle dots on heart surface with glow filter
- Brighten heart metal fill for better visibility against dark bg
- Update headline gradient to dark metallic gold (no white tones)
- Apply gradient-text to all section headings for consistency
- Warm gold subtitle color in hero

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/styles/animations.css

@@ -133,7 +133,15 @@
 /* ===== Gradient Text ===== */
 
 .gradient-text {
-  background: linear-gradient(135deg, #fff 0%, #c9a96e 50%, #fff 100%);
+  background: linear-gradient(
+    135deg,
+    #8a6f3e 0%,
+    #c9a96e 20%,
+    #8a6f3e 40%,
+    #c9a96e 60%,
+    #6b5530 80%,
+    #8a6f3e 100%
+  );
   background-size: 200% 200%;
   -webkit-background-clip: text;
   background-clip: text;