Debian Bookworm + Chrony in a Dual-Boot Setup: Why Windows and Linux Disagree on Time & Solution

In a dual-boot setup, Linux treats the hardware clock (RTC) as UTC while Windows treats it as local time, causing both OSes to show incorrect time after rebooting between them. The common fix `timedatectl set-local-rtc 1` can still fail when Chrony's `rtcsync` directive writes the RTC back in UTC at runtime, overriding the local-time setting and breaking Windows time again on reboot.