[Proposal] Handler for default values in bpy.property to handle units setups

Current situation
Default values dosen’t handle any units settings.

What’s the point ?
Creating real-wold asset like landscape / nuts and bolts require to handle real units in defaults.

Sample for landscape having default set say to 1000 (units) where the dev expect unit setup to be meters while user hope km result in a landscape of 1000 km.

Proposed solution:
Defer responsability to addon devs by using an optional “preprocess_default” method on bpy.Properties.

Ideal preprocess_default signature could be preprocess_default(rna_property_definition or self, value) and must be called to transform default value before applying any bounds checks as currently done in regular default handler.
So addon devs may properly handle units setup and return the value to actual default handler.