(20241219) SMS module fully re-organized.

models/core/message.py

@@ -82,11 +82,12 @@ import datetime
 
 class CoreMessageModel(BaseModel):
 
-    messageId: ObjectId = Field(
+    messageId: ObjectId | None = Field(
         description = "the id of the document in mongodb that holds this information",
         frozen = True,
         default = None,
-        alias = "_id"
+        alias = "_id",
+        exclude = True
     )
 
     ts: AwareDatetime = Field(
@@ -291,7 +292,7 @@ if __name__ == "__main__":
         },
         sender = "Polki",
         chat = "T6 Cats",
-        preview = "Hi, there! How do you do?"
+        snippet = "Hi, there! How do you do?"
     )
 
     print("MESSAGE MODEL:", json.to_string(message.model_dump(), default = str))