Fix/default weight unit

[Huncsuga]

Description

• This PR fixes an issue where newly created product variants default their weight_unit to mm, which is a length unit and not a valid weight measurement.

• When a product is created the weight unit, the system automatically assigns mm as the default value in the database. This leads to incorrect behavior in features that rely on weight-based logic, such as shipping calculations.

• This change ensures that product variants use a valid weight unit by default.

Related Issue

• Fixes Product variant weight_unit defaults to mm instead of a valid weight unit #2383

Type

• Bug fix

What was changed

• Corrected the default value of weight_unit for product variants

• Ensured the default unit represents a valid weight measurement (kg)

Expected Outcome

• Newly created product variants no longer default to an invalid weight unit

• Weight-based calculations (e.g. shipping) behave consistently

• Data stored in the database correctly reflects weight semantics

How to test

• Create a new product in the Lunar admin panel

• Inspect the weight_unit value in the database

• Verify that the unit defaults to a valid weight unit (e.g. kg) and not mm

[alecritson]

We shouldn't be doing any data changes within migrations, instead use a state update class. See the database/state folder for how these are structured :)

[Huncsuga]

@alecritson Thanks for the PR comment! I’ve updated it.