Feature Request: Support battery swapping/rotation workflow when logging charge cycles

Problem

Grocy's battery tracking works well for individual batteries, but swapping rechargeable batteries between devices (e.g., spare 9V NiMH batteries in smoke detectors) requires manual updates to the field "Used in" for both batteries every time.

Proposed Feature

When logging a charge cycle ("Track charge"), add an optional field (only if "Used In" is in use):

"Replace battery currently in device with:" → dropdown to select another existing battery.

On save:

• empty "Used in" on the selected battery
• fill in "Used in" on the newly selected battery

Benefits

• Faster, less error-prone workflow for common rotation scenarios (smoke detectors, power tools, safety equipment).
• Keeps per-battery cycle history accurate.

Thanks for considering!