style(web/swarm): align Swarm pages with shared page-header primitive

decnet_web/src/components/Swarm.css

@@ -1,16 +1,34 @@
-.dashboard-header {
+.swarm-root .page-header {
   display: flex;
-  align-items: center;
+  align-items: flex-end;
   justify-content: space-between;
+  gap: 24px;
+  padding-bottom: 16px;
   margin-bottom: 24px;
+  border-bottom: 1px solid var(--panel-border);
 }
 
-.dashboard-header h1 {
+.swarm-root .page-title-group {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.swarm-root .page-header h1 {
   display: flex;
   align-items: center;
-  gap: 12px;
-  font-size: 1.4rem;
-  letter-spacing: 2px;
+  gap: 10px;
+  font-size: 1.3rem;
+  letter-spacing: 4px;
+  font-weight: 700;
+  margin: 0;
+  color: var(--matrix);
+}
+
+.swarm-root .page-sub {
+  font-size: 0.7rem;
+  opacity: 0.5;
+  letter-spacing: 1px;
 }
 
 .panel {