fix: deduplicate cumulative voice results (Closes #935)

frontend/voice-issue-capture.js

@@ -43,6 +43,7 @@ function createVoiceIssueCapture({
     recognition.interimResults = false;
     recognition.onresult = event => {
       const finalText = Array.from(event.results || [])
+        .slice(event.resultIndex ?? 0)
         .filter(result => result.isFinal)
         .map(result => result[0]?.transcript || '').join(' ').replace(/\s+/g, ' ').trim();
       if (finalText) {