docs: Add gradient with noise texture to docs home page hero section (#69106)

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: ian.alton@airbyte.io <ian.alton@airbyte.io>

docusaurus/src/pages/index.module.css

@@ -5,7 +5,9 @@
 
 /* Section 1: Hero */
 .heroSection {
-  background: var(--ifm-color-primary);
+  background: 
+    linear-gradient(144deg, rgba(97,94,255,1) 45%, rgba(0,0,0,0)),
+    url(/noise.svg);
   padding: 4rem 0;
 }
 

docusaurus/static/noise.svg

@@ -0,0 +1,11 @@
+<svg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'>
+  <filter id='noiseFilter'>
+    <feTurbulence 
+      type='fractalNoise' 
+      baseFrequency='9.63' 
+      numOctaves='3' 
+      stitchTiles='stitch'/>
+  </filter>
+  
+  <rect width='100%' height='100%' filter='url(#noiseFilter)'/>
+</svg>