review the reader browser window lifecycle in main process

[panaC]

Features list:

• Renamed pubId and winId for clarity and consistency
• Removed/Comment win.registry redux state/reducer/actions, no longer needed.
• Added reader_pub from synced actions (sender key)
• Refactored reader open/close logic to use saga generator actions instead of Redux actions
• Fixed and improved winBound behavior (new reader windows are offset and no longer overlap the library window)
• Added readingFinished handling
• Reviewed browser window startup lifecycle (reader initialization and closing flow)
• Replaced global reader Redux state persistence with atomic persistence via synced actions (config / locator)
• Removed the reader session feature (no longer saves and restores multiple reader states across restarts)

[panaC]

supersede and close #3455

[panaC]

Fixes #3439