Reading Library V4.3.12 — permanent updater bootstrap

This release changes the Windows update architecture so the updater no longer tries to replace the script that is currently running.

• BRL_Update.ps1 is now a small permanent bootstrap launcher.
• The graphical updater lives in BRL_Update_Engine.ps1.
• Every update run copies the engine to a temporary Windows folder first.
• The temporary engine can safely replace both permanent updater files during an update.
• Future update downloads can therefore show the customer-facing progress window reliably.
• The graphical updater shows downloaded MB / total MB, percentage complete, MB remaining, download speed and estimated time left.
• Installation progress shows files installed / total files and files remaining.
• Existing safety checks remain: HTTPS, SHA-256 verification, application backup and rollback where possible.

Transition note:
An installation that still has the legacy updater may show the old blue PowerShell download screen once while installing V4.3.12. After V4.3.12 is installed, subsequent updates use the new bootstrap + temporary graphical engine architecture.
