content(about): wire Khabran's bio + multi-paragraph render

Bio embedded as \n\n-delimited string; render splits on that boundary
into per-para <p class="bio-body">. Adjacent-sibling margin keeps
stacked paragraphs readable. Daniel's single-para bio is unaffected.

DeepDrftPublic.Client/Pages/About.razor.css

@@ -321,6 +321,10 @@
     opacity: 0.7;
 }
 
+.bio-body + .bio-body {
+    margin-top: 0.75em;
+}
+
 /* ── Inset framed figure (gear shot) with rail-side caption ── */
 .movement-figure {
     margin: 5rem 0 0;