- Removed JavaScript scroll event listeners and console.log debugging
- Removed WebViewCoordinator.updateScrollProgress() method
- Removed onExternalScrollUpdate callback
- Removed webView reference and lastSentProgress from coordinator
- Restored scrollViewHeight state variable
- Restored JumpButton functionality with ScrollPosition
- Back to onScrollPhaseChange with 3% threshold for reading progress
The JavaScript approach didn't work because WebView scrolling is disabled
(embedded in SwiftUI ScrollView). The SwiftUI-based solution is cleaner
and performs well with onScrollPhaseChange.