Track whether a keydown should perform text insertion separately from
the delivered code point. Native frontends and text-oriented test paths
can now mark events that came from text input, while shortcut-style key
events keep Alt-modified default insertion suppressed.
This lets macOS Option-generated text such as Option+A and Option+Space
insert into editable controls without making plain Alt shortcuts insert
their base character. Add coverage for Alt text, Ctrl+Alt text,
separator text, Ctrl-only shortcuts, and Alt shortcuts.
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