What's fixed

• Testing Mode can no longer lock a file: a stuck state is detected and repaired automatically.
• New Fix Stuck Testing Mode / Force Exit Testing Mode button — one click restores the viewport, collections and addon state.
• Opening a project saved during Testing Mode now repairs it on load.
• Pressing Enter LODs Testing Mode on an inconsistent state now recovers and starts instead of refusing.
• Safety: exiting Testing Mode after an undo can no longer delete mesh data.
• General robustness: the testing session now shuts down cleanly even if something goes wrong internally.

If you are currently stuck: update the addon, open your project and click Fix Stuck Testing Mode. Back up your file first if it was saved while Testing Mode was active, and check your modifiers before re-enabling them.