fix(ui): delete prompts use data-confirm, so a quote in a name no longer runs script (#5099)

#5099 "A name containing a quote runs script when an admin clicks Delete".
Inline handlers like onclick="return confirm('Delete {{ rule.name }}?')" are
HTML-decoded before the JavaScript is parsed, so autoescaping did not stop a
name such as  x');fetch(…);//  from running.

- Every prompt (22 handlers, plus the docker prune and token revoke ones)
  is now data-confirm="…", read through dataset by one submit listener in
  base.html; nothing rendered is parsed as JavaScript.
- The remaining inline handlers take integers only (|int), and the time
  range buttons pass this.dataset.range.
- tests/test_inline_handlers.py fails on any {{ }} in an inline handler that
  is not |int, with a self-test; tests/_templates.py is the one template
  walker the template guards now share.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/host_agent/templates/settings_list.html

@@ -156,12 +156,12 @@
         <td class="td-actions">
           <form method="post" action="/plugins/host_agent/fleet/{{ item.reg.host_id }}/rotate-token"
                 style="display:inline;"
-                onsubmit="return confirm('Rotate the token for this host? The existing agent will stop working until reinstalled with the new token.');">{{ csrf_field() }}
+                data-confirm="Rotate the token for this host? The existing agent will stop working until reinstalled with the new token.">{{ csrf_field() }}
             <button type="submit" class="btn btn-ghost btn-sm">Rotate token</button>
           </form>
           <form method="post" action="/plugins/host_agent/fleet/{{ item.reg.host_id }}/delete"
                 style="display:inline;"
-                onsubmit="return confirm('Delete this host registration? The agent will be unable to report metrics until re-registered.');">{{ csrf_field() }}
+                data-confirm="Delete this host registration? The agent will be unable to report metrics until re-registered.">{{ csrf_field() }}
             <button type="submit" class="btn btn-danger btn-sm">Delete</button>
           </form>
         </td>