GDE: Add Lock/Read-only into Column context menu

Few times, I accidentally erased (with the help of GDE glitches when you type in Search, but the text goes to cell in a table) values in columns that are calculated with Google Sheets (e.g. with ARRAYFORMULA).

And the worst thing is that you can’t fix #REF! error in Glide. Only possible when you open GS and clear that typo.

Would be good to have a lock for these columns