refactor button elements; change button types for search and filter actions in admin pages

public/admin/assets/css/layout.css

@@ -95,27 +95,28 @@ header.app-header h1 span {
 
 
 /* ── stats bar ── */
+/* each .stat owns its own horizontal padding so the vertical separator
+   renders edge-to-edge; no margin gap between cells. */
 
 .stats-bar {
   display: flex;
-  gap: 0;
   background: var(--bg-card);
   border-bottom: 1px solid var(--border);
-  padding: 0 24px;
   flex-wrap: wrap;
 }
 
 .stat {
   display: flex;
   flex-direction: column;
-  gap: 3px;
-  padding: 14px 28px 14px 0;
-  margin-right: 28px;
+  justify-content: center;
+  gap: 4px;
+  padding: 16px 32px;
   border-right: 1px solid var(--border);
-  padding-right: 28px;
+  flex: 0 0 auto;
 }
 
-.stat:last-child { border-right: none; }
+.stat:first-child { padding-left: 24px; }
+.stat:last-child  { border-right: none; }
 
 .stat .label {
   color: var(--muted-dark);