Webapp redesign: fixes from the functional regression test

- Unattend: a command's '...' menu stayed open after Move up/down and
  covered the next row's menu, so the next click could stage removing the
  wrong command. The menu now closes and focus returns to its button.
- '...' menus close on an outside click, on Escape and when another
  opens (static/app.js), for every page.
- Drivers: Remove asks to confirm again, as before the redesign. Long zip
  paths in a row body wrap (the page scrolled sideways at 390 px).
- Rollback review returns to the page it was opened from (Dell page or
  Updates overview), for both Cancel and the rollback itself.
- To-do: the ServiceNow period offers a year again (366 days).
- Imaging floor: a search that matches a log-only bay opens that group;
  its open state survives the live refresh. 'Clear all' states the
  number of session files it deletes, hidden finished ones included.
- Dashboard: the image key pattern is valid under the browser's v flag
  (client-side validation was silently skipped).
- Import: allowed_import_source() compares real paths, so
  '<upload dir>/../..' is refused. This path traversal predates the
  redesign; the import moves the source tree, so it mattered.

webapp/templates/dashboard.html

@@ -107,7 +107,7 @@
           <div class="form-field">
             <label class="form-label">Key</label>
             <input type="text" class="form-control mono" name="key"
-                   pattern="[a-z][a-z0-9-]{1,63}" required
+                   pattern="[a-z][a-z0-9\-]{1,63}" required
                    placeholder="gea-shopfloor-newtype">
             <div class="form-text">Lowercase + hyphens. Used as directory name + URL path. 2-64 chars, must start with a letter.</div>
           </div>
@@ -144,7 +144,7 @@
           <div class="form-field">
             <label class="form-label">New key</label>
             <input type="text" class="form-control mono" name="dst_key"
-                   pattern="[a-z][a-z0-9-]{1,63}" required>
+                   pattern="[a-z][a-z0-9\-]{1,63}" required>
           </div>
           <div class="form-field">
             <label class="form-label">Friendly name (optional)</label>