Implement user persona creation and update logic in database

- Enhanced `update_user_persona` function to first check for an existing persona before updating.
- If no persona exists, a new record is created with the provided updates and a timestamp.
- This change improves data integrity by ensuring that user personas are accurately maintained in the database.

database.py

@@ -214,11 +214,26 @@ async def update_user_persona(wa_id: str, updates: dict):
     
     try:
         updates_with_ts = {**updates, "updated_at": datetime.utcnow().isoformat()}
-        supabase\
-            .table("personas")\
-            .update(updates_with_ts)\
-            .eq("wa_id", wa_id)\
-            .execute()
+        
+        # First try to get existing persona
+        existing = supabase.table("personas").select("*").eq("wa_id", wa_id).execute()
+        
+        if existing.data:
+            # Update existing record
+            supabase\
+                .table("personas")\
+                .update(updates_with_ts)\
+                .eq("wa_id", wa_id)\
+                .execute()
+        else:
+            # Create new record
+            new_persona = {
+                "wa_id": wa_id,
+                "created_at": datetime.utcnow().isoformat(),
+                **updates_with_ts
+            }
+            supabase.table("personas").insert(new_persona).execute()
+            
     except Exception as e:
         print(f"Error updating user persona: {e}")