Card layout for tables on phones and tablets; fit terminal bar

Sideways-scrolling tables only showed a few of the 11 columns at a time on
a phone or iPad. Below 1100px (where the nav already collapses) each row
now renders as a card: the device as the title and every other column as
a labelled line, one card per row on phones and two or more on tablets.

- web/mobile.js copies column names onto cells (data-label) for the cards
  and re-applies them as the dashboard re-renders; no-op on wide screens
- Column filters fold behind a "Show filters" button with an active count
- Custom View keeps its sort/filter header as a strip of chips
- Terminal: Follow and the "your actions (simulated)" legend move into the
  terminal window's title bar; tabs read "Server" / "Worker" on phones, so
  LIVE, the legend and Follow are all visible on small screens

web/index.html

@@ -352,6 +352,7 @@
         }
     </style>
     <link rel="stylesheet" href="/mobile.css">
+    <script src="/mobile.js"></script>
 </head>
 <body>