style(docs): Add vertical-align middle to base badge rule

why: Standalone {badge} in prose text was misaligned with surrounding
text. The heading flex and link rules handled their contexts, but the
base rule had no vertical-align.

Author: tony

docs/_static/css/custom.css

@@ -258,6 +258,7 @@ h4:has(> .sd-badge) {
 .sd-badge {
   display: inline-flex !important;
   align-items: center;
+  vertical-align: middle;
   gap: 0.28rem;
   font-size: 0.67rem;
   font-weight: 650;