Phone Jump button; docs never scroll sideways; presence sweep timing kept

- Jump (phones / tablets): find a device by name and scroll to its card, or
  jump to a section, the top or the bottom of the page.
- Documentation on phones: long paths, links, code and tables wrap; toolbar is
  title, last edited, then the buttons.
- Filter bar's Clear is the only clear button on phones.
- Card fields: search box and add list as wide as the field rows.
- Presence sweep: the demo uses the hourly schedule too, and the last sweep
  time survives a worker restart (a restart used to trigger an extra sweep).

web/index.html

@@ -360,6 +360,7 @@
     <script src="/overview.js"></script>
     <script src="/docs.js"></script>
     <script src="/router.js"></script>
+    <script src="/jump.js"></script>
     <script src="/excel-filter.js" defer></script>
 </head>
 <body>