ui: stop Run-now buttons wrapping to two lines

Three sites:
* Schedules list per-row Run-now / Edit / Delete column was 1fr
  next to a 1.3fr retention column — too narrow for the three
  buttons. Pin the action column to 240px and add
  whitespace-nowrap to each button so the layout can't squeeze
  them onto two lines regardless.
* Dashboard host_row Run-now button got whitespace-nowrap +
    for the same reason inside the 92px action column.
* Host detail header "Run backup now" —   the words so the
  button never breaks across lines if the header gets crowded.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/templates/pages/host_detail.html

@@ -39,7 +39,7 @@
     </div>
     <div class="flex items-center gap-2">
       {{if eq $host.Status "offline"}}
-        <button class="btn" disabled title="agent is offline">Run backup now</button>
+        <button class="btn" disabled title="agent is offline">Run&nbsp;backup&nbsp;now</button>
       {{else if not $host.RepoInitialisedAt}}
         <button class="btn btn-danger"
                 hx-post="/hosts/{{$host.ID}}/init-repo"
@@ -50,7 +50,7 @@
         <button class="btn btn-primary"
                 hx-post="/hosts/{{$host.ID}}/run-backup"
                 hx-swap="none"
-                hx-disabled-elt="this">Run backup now</button>
+                hx-disabled-elt="this">Run&nbsp;backup&nbsp;now</button>
       {{end}}
       <button class="btn">Edit credentials</button>
       <button class="btn btn-ghost text-base px-2.5">⋯</button>