Always show store filter dropdown on results table

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/src/routes/results/+page.svelte

@@ -154,14 +154,12 @@
                  text-text-primary placeholder-text-tertiary focus:border-accent/50 focus:outline-none transition-colors" />
       </div>
 
-      {#if storeNames().length > 1}
       <select bind:value={filterStore} class="input-field w-auto text-xs py-1 px-2">
         <option value="">All stores</option>
         {#each storeNames() as name}
           <option value={name}>{name}</option>
         {/each}
       </select>
-      {/if}
 
       <span class="text-2xs text-text-tertiary">
         {filteredAndSorted().length} of {results.length} shown