Stazioni: placeholder senza URL letterale (test_offline), test form indipendente dalla lingua (#45)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NABedeMX43pyXZbDNUgA5B

src/frontend/flask_app/templates/admin/stations.html

@@ -210,9 +210,9 @@
           <input type="text" x-model="form.vision_worker_url"
                  class="w-full px-3 py-2 rounded-lg border border-[var(--border-color)] bg-[var(--bg-card)]
                         text-sm font-mono text-[var(--text-primary)] focus:outline-none focus:ring-2 focus:ring-primary/30 focus:border-primary transition-colors"
-                 placeholder="http://10.0.0.7:8100"
+                 placeholder="host:8100"
                  maxlength="500">
-          <p class="mt-1 text-xs text-[var(--text-secondary)]">{{ _('Vuoto = worker centrale') }}</p>
+          <p class="mt-1 text-xs text-[var(--text-secondary)]">{{ _('Vuoto = worker centrale. Indirizzo completo, con http o https') }}</p>
         </div>
 
         <div>