fix: multi-language placeholder in contact_schema (store validation)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TNSsmqpNe4BGMp59AmkvJr

Author: claude

gladys-assistant-integration.json

@@ -57,7 +57,7 @@
         "fr": "Votre numéro de téléphone au format international, ex. +33612345678."
       },
       "required": true,
-      "placeholder": "+33612345678"
+      "placeholder": { "en": "+33612345678", "fr": "+33612345678" }
     },
     {
       "key": "api_key",