feat: Машины - column names centred over their values

internal/server/web/static/app.css

@@ -1055,3 +1055,9 @@ body.no-motion *, body.no-motion *::before, body.no-motion *::after, body.no-mot
 .btn.close.x { flex:none; aspect-ratio:1; min-width:0; }
 .ai-head .ai-close { width:32px; height:32px; }
 .addmenu .ico .dot { display:inline-block; vertical-align:middle; }
+/* Машины: each column's name over the middle of its values (on a computer;
+   a phone lays the rows out as blocks). */
+@media (min-width: 641px) {
+  table.machines th, table.machines td { text-align:center; }
+  table.machines td.actions .row { justify-content:center; }
+}

internal/server/web/templates/dashboard.html

@@ -3,7 +3,7 @@
   <h1>Машины-клиенты</h1>
   <div class="card">
     {{if .Agents}}
-    <table class="stack">
+    <table class="stack machines">
       <thead><tr><th>Статус</th><th>Имя</th><th>Hostname</th><th>ОС / Арх</th><th>Активность</th><th>Действия</th></tr></thead>
       <tbody>
       {{range .Agents}}