fix(dashboard): collapse header on mobile (≤700px)

Hide tagline, version tag, and Phone Setup on narrow viewports so
the header stays single-row: logo + status dot + blocking toggle.
Reduces logo font-size from 1.8rem to 1.4rem on mobile.

site/dashboard.html

@@ -552,7 +552,11 @@ body {
 @media (max-width: 700px) {
   .stats-row { grid-template-columns: repeat(2, 1fr); }
   .dashboard { padding: 1rem; }
-  .header { padding: 1rem; }
+  .header { padding: 0.8rem 1rem; }
+  .logo { font-size: 1.4rem; }
+  .tagline { display: none; }
+  #headerVersion { display: none; }
+  #phoneSetup { display: none; }
 }
 </style>
 </head>