The 8 drifting timers ([TimerDrift]) change wire format from delta to anchored
time, so each class bumps its serialization version with a MigrateFrom that
replays the old delta read through the migration schema. The 2 wall-clock
timers (Aquarium, FountainOfLife) keep their format via wallClock: true with
no bump. Restart methods drop their TimeSpan.MinValue sentinel checks - v4
invokes them only when a timer was actually running at save.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
