fix(tui): preserve Ctrl+J newline in VTE terminals - #51546

Thanks for the triage. To clarify scope: this PR fixes the TypeScript TUI renderer path in ui-tui/src/components/textInput.tsx, specifically shouldPreserveCtrlJNewline() and its Vitest coverage.

I saw the related PR #52102, which addresses the Python CLI predicate in cli.py. That appears to be the same root cause at a different layer rather than a direct duplicate.

Happy to do whichever maintainers prefer:

1. keep this PR focused on the TypeScript renderer layer,
2. expand this PR to also cover the Python CLI predicate, or
3. close this in favour of a combined maintainer-preferred patch.

My preference is to keep both layers covered, since VTE detection seems relevant in both input paths.

Thanks for the focused TUI fix. Current main still lacks a VTE_VERSION branch in shouldPreserveCtrlJNewline() (ui-tui/src/components/textInput.tsx:128-150), while the composer sends bare-LF return events to the submit path unless that predicate is true (ui-tui/src/components/textInput.tsx:990-1000). The added predicate case and VTE regression test match that control flow.

The target files are unchanged from the PR's merge base through current HEAD (git diff --quiet 070ac2a71900f30b680ecafd4d68c162e9089a0a..HEAD -- ui-tui/src/components/textInput.tsx ui-tui/src/__tests__/textInputPassThrough.test.ts), so this remains a clean, focused salvage candidate. The related Python CLI path is separately addressed by #52102, consistent with the contributor's clarification.

Automated hermes-sweeper review.

Heads up: #98289 started as a superset of this PR. I wrote the fix before
finding this one, and it carried the same VTE_VERSION hunk in
shouldPreserveCtrlJNewline(). I have removed that hunk from #98289 so it now
depends on this PR rather than competing with it. #98289 keeps only the
extended-key advertisement in hermes-ink and the TERM fingerprints for
alacritty, foot, kitty and ghostty. This PR should merge first.