Fix views/controllers/router: command palette, create form, admin views

- Consolidate the duplicated command palette to a single overlay + init in
  the footer; fix New Ticket to route to /ticket/create (was a 404 /create);
  keep the CSP nonce and all commands
- TicketController create(): trim title, require a non-empty description,
  and honor the posted status (validated against the canonical list) instead
  of silently discarding it
- UserActivityView: 'Active Users' counts only users active in the selected
  range, not every registered user
- layout_footer/DashboardView: local esc() now escapes quotes so values used
  in HTML attributes can't break out
- TicketView: comments tab badge shows the true total, not just page one
- layout_header: gate the 'View activity log' link behind the admin flag
- index.php: validate /admin/user-activity date params; anchor the legacy
  /ticket.php route; align the audit action-type whitelist with the dropdown
- ApiKeysView: correct the external API sample to /create_ticket_api.php

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

views/admin/ApiKeysView.php

@@ -132,7 +132,7 @@ include __DIR__ . '/../../views/layout_header.php';
     </p>
     <div class="lt-code-block">
       <div class="lt-code-header"><span class="lt-code-lang">CURL</span></div>
-      <pre><code>curl -X POST https://your-instance/api/create_ticket.php \
+      <pre><code>curl -X POST https://your-instance/create_ticket_api.php \
   -H "Authorization: Bearer YOUR_API_KEY" \
   -H "Content-Type: application/json" \
   -d '{"title":"My ticket","category":"General","type":"Issue","priority":3}'</code></pre>