🐛(frontend) ensure transcript segments are sorted by their timestamp

Switching from Deepgram to our custom Kyutai implementation introduced changes
in how segment data is returned by the LiveKit agent, so the segment start time
is now treated as optional.

CHANGELOG.md

@@ -23,6 +23,7 @@ and this project adheres to
 - ♿️(frontend) announce copy state in invite dialog #877
 - 📝(frontend) align close dialog label in rooms locale #878
 - 🩹(backend) use case-insensitive email matching in the external api #887
+- 🐛(frontend) ensure transcript segments are sorted by their timestamp #899
 
 ## [1.3.0] - 2026-01-13