It turns out that `event.key` for ctrl/cmd+Z is `z`, and it’s `Z` for
ctrl/cmd+shift+Z.

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Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>

Removing
- Debugger
- `perf-deeets`
- `codemirror`

* Prevent Cmd+Z/Cmd+Shift+Z from propagating to the browser

* Allow browser to handle undo/redo shortcuts in input fields

* Don’t change a transaction’s note from null to ''

*  (prettier) adding trailing commas

* More commas

* Allow bypassing SharedArrayBuffer override

* Make an attempt to avoid merging budgets

* Update FatalError.js

* s/allowBuggyFallback/isSharedArrayBufferOverrideEnabled/

Co-Authored-By: Matiss Janis Aboltins <886567+MatissJanis@users.noreply.github.com>

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Co-authored-by: Matiss Janis Aboltins <886567+MatissJanis@users.noreply.github.com>