Revert to local timezone display for user-facing times

- Changed formatTime back to use toLocaleTimeString (local time)
- Changed formatDateTime back to use toLocaleString (local time)
- App now displays all times in user's local timezone
- Backend still stores times in UTC, frontend converts for display

scripts/e2e.sh

@@ -36,8 +36,13 @@ npm run generate-api-types
 cd ..
 
 # Run tests (suppress Node.js color warnings)
+# If TEST argument is provided, use it as a file pattern
 cd frontend
-NODE_NO_WARNINGS=1 npm run test:e2e
+if [ -n "$1" ]; then
+	NODE_NO_WARNINGS=1 npx playwright test "$1"
+else
+	NODE_NO_WARNINGS=1 npm run test:e2e
+fi
 EXIT_CODE=$?
 
 # Cleanup