Extract Grid Style 9 post featured image background properties

- Add background-repeat: no-repeat, background-position: center center, background-size: cover
- Include height: 100%, position: relative, overflow: hidden, margin: 0
- Add comprehensive CSS transitions for all browsers with 0.5s ease timing
- Apply .pp-content-post-grid parent scoping to prevent global conflicts

Author: pftg

themes/beaver/assets/css/utilities/components/powerpack/content-grid.css

@@ -227,4 +227,20 @@
 
 .pp-content-post-grid .pp-content-post.pp-grid-style-9 .pp-content-grid-image {
   height: 100%;
+}
+
+/* Grid Style 9 Post Featured Image Background */
+.pp-content-post-grid .pp-content-post.pp-grid-style-9 .pp-post-featured-img {
+  background-repeat: no-repeat;
+  background-position: center center;
+  background-size: cover;
+  height: 100%;
+  position: relative;
+  overflow: hidden;
+  margin: 0;
+  -webkit-transition: all 0.5s ease;
+  -moz-transition: all 0.5s ease;
+  -ms-transition: all 0.5s ease;
+  -o-transition: all 0.5s ease;
+  transition: all 0.5s ease;
 }