fix(admin): use form-input class on scenario filter fields

The search/country/venue-type inputs used class="input" which has no
definition in input.css — falls back to the browser's default focus
outline. Replaced with form-input to get the consistent focus ring
(ring-2 / ring-electric / border-electric) used everywhere else in admin.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/padelnomics/admin/templates/admin/scenarios.html

@@ -22,11 +22,11 @@
       <label class="block text-sm text-slate mb-1">Search</label>
       <input type="text" name="search" value="{{ current_search }}"
              placeholder="Title, location, slug…"
-             class="input w-full">
+             class="form-input w-full">
     </div>
     <div>
       <label class="block text-sm text-slate mb-1">Country</label>
-      <select name="country" class="input">
+      <select name="country" class="form-input">
         <option value="">All countries</option>
         {% for c in countries %}
         <option value="{{ c }}" {% if c == current_country %}selected{% endif %}>{{ c }}</option>
@@ -35,7 +35,7 @@
     </div>
     <div>
       <label class="block text-sm text-slate mb-1">Venue type</label>
-      <select name="venue_type" class="input">
+      <select name="venue_type" class="form-input">
         <option value="">All types</option>
         {% for v in venue_types %}
         <option value="{{ v }}" {% if v == current_venue_type %}selected{% endif %}>{{ v | capitalize }}</option>