Read-Only mode

Feature request: I'm working with an existing Notion instance, and I'd really like to make sure I don't accidentally wipe any data.

Could the Client be created with a read-only flag to ensure that I can't e.g. accidentally assign something to a property?

(open to temporary hacks too!)

Start by locating the Client entry point and tracing the operations that can assign properties or otherwise modify the Notion instance. Define how a read-only flag is passed when creating the Client and which mutation paths it must protect; done means attempted writes are consistently prevented without affecting read operations.

Written by the indexing model from the issue text.