QV vote button hardcoded to English under non-English locale

[hankpan99]

Problem

On the regular QV vote stage, the navigation button is hardcoded to English (Next Question → / Next Module →) and ignores the survey locale. Under zh-TW, respondents see English instead of Chinese.

(QVPlus flow is unaffected — already fixed separately.)

When it happens

• Survey has 2+ QV questions → button shows Next Question →.
• QV block is followed by another module → button shows Next Module →.
• A single trailing QV question is fine (falls through to localized Submit).

The hardcoded code

client/src/pages/survey/components/QuadraticSurveyPage.tsx:246-250:

const votePrimaryLabel = !isLastNavigatorQuestion
  ? 'Next Question →'      // <-- hardcoded English
  : hasNextModule
    ? 'Next Module →'      // <-- hardcoded English
    : undefined;

This is passed to QsNavBar as voteCtaLabel. In QsNavBar.tsx:245:

voteCtaLabel || (voteCtaMode === 'next' ? labels.text.nextQuestion : labels.text.submit)

the hardcoded voteCtaLabel shadows the already-localized labels.text.nextQuestion (下一題 →), so the translation is never used.

Fix

• Replace the literals with resolvedQvLabels.text.nextQuestion / a new nextModule key (only nextQuestion is translated today; Next Module → has none).
• Do it on a branch off main (touches the shared/regular QV path).