Zig's KeyEvent.utf8 and the embedded API's key/preedit text are byte
slices passed through to key encoding and the pty; the port converted
them lossily to UTF-8.
- KeyEvent.utf8 is &[u8] end to end (ghostty-input encoder, core,
ghostty-lib C API, libghostty-vt key events, GTK callers). Where Zig
validates with Utf8View (alternates, modify-other-keys, ctrl CSI-u,
associated text, binding unicode lookup) invalid text takes the same
"no UTF-8" fallback.
- Invalid preedit UTF-8 behaves like Zig's `try Utf8View.init`: the
prior preedit is cleared and marked dirty, the callback returns an
error (logged by the C API) and no preedit is set.
- The inspector key widget shows invalid key text lossily, display only.
Test Plan:
- cargo test --workspace --no-fail-fast (3407 passed)
- cargo test -p ghostty-lib --features test-platform (C-API key text
0xff 0xfe reaches the pty unchanged)
- just check-macos (both), just check-windows, just check-wasm