Preserve the rest timer when correcting logged reps

[Felixre7]

fixes: #979

Fix

• RecordedWeightedExercise.withRepCount keeps the set's original completion time.
• Editing reps no longer resets a paused or dismissed rest timer; it only resets the timer when a set is actually (un)logged.
• A failure state captured when the timer starts (failedAtStart) is carried through pause/resume so the rest window and notifications stay consistent with the logged set.

[github-actions]

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