Violet replies to unregistered guests with friendly signup prompt

Instead of a silent error event, guests who PM Violet now see their
message echoed back plus a flirty reply telling them to register.

app.py

@@ -690,7 +690,16 @@ def on_pm_message(data):
     # Route to AI if recipient is Violet
     if room.endswith(f":{AI_BOT_NAME.lower()}"):
         if not user.get("user_id") and not user.get("is_admin"):
-            emit("error", {"msg": "You must be registered to chat with Violet."}); return
+            # Echo their message, then reply as Violet
+            emit("pm_message", payload, to=sid)
+            emit("pm_message", {
+                "from": AI_BOT_NAME,
+                "text": "Hey hun 💜 You'll need to register an account before we can chat. "
+                        "Go back and sign up — I'll be waiting for you! 😘",
+                "room": room,
+                "ts":   _ts(),
+            }, to=sid)
+            return
         if not user.get("has_ai_access") and user.get("ai_messages_used", 0) >= AI_FREE_LIMIT:
             emit("ai_response", {"error": "ai_limit_reached", "room": room}, to=sid)
             return