(20241231) Too many thing happening...

models/core/auth_token.py

@@ -173,10 +173,16 @@ class CoreAuthTokenModel(BaseModel):
         default = "pending"
     )
 
-    syncFreq: Literal[60, 300, 900, 1500] = Field(
+    syncFreq: Literal[None, 60, 300, 900, 1500] = Field(
         description = "the no. of seconds after which to poll for updates from the client (if applicable)",
         frozen = False,
-        default = 300
+        default = None
+    )
+
+    lastSyncTs: AwareDatetime | None = Field(
+        description = "the time at which this client's updates were last polled",
+        frozen = False,
+        default = None
     )
 
     # ┏┓    ┏•