feat: Add support for toggling readonly mode.

[gonfunko]

The basics

• I validated my changes

The details

Resolves

Fixes #8732

Proposed Changes

This PR adds a setIsReadOnly() method to Workspace that allows dynamically toggling readonly status at runtime. Previously, the readonly option could only be set at injection time, and thus required reinjecting the workspace to modify.

For backwards compatibility, the readOnly field in the options dictionary is updated when the state is changed, since this was previously the only way to observe the readonly status. A getter, isReadOnly(), has also been introduced, and core has been refactored to use it.

Reason for Changes

This unblocks #8732, but also has potential instructional usecases.