Fix login data structure and improve voice input UX

- Fix login endpoint to return families as array of objects instead of strings
- Update auth interface to match /auth/me endpoint structure
- Add silence detection to voice input (auto-stop after 1.5s)
- Add comprehensive status messages to voice modal (Listening, Understanding, Saving)
- Unify voice input flow to use MediaRecorder + backend for all platforms
- Add null checks to prevent tracking page crashes from invalid data
- Wait for auth completion before loading family data in HomePage

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

maternal-web/app/track/diaper/page.tsx

@@ -619,6 +619,11 @@ export default function DiaperTrackPage() {
                 <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
                   {recentDiapers.map((activity, index) => {
                     const data = activity.data as DiaperData;
+                    // Skip activities with invalid data structure
+                    if (!data || !data.diaperType) {
+                      console.warn('[Diaper] Activity missing diaperType:', activity);
+                      return null;
+                    }
                     return (
                       <motion.div
                         key={activity.id}