feat: Add region CRUD to catalog SQL driver

[mashawes]

feat: add region CRUD to catalog-driver-sql (#723)

Extends the catalog-sql driver with region CRUD, following the existing SQL-driver patterns.

• Adds Region / RegionCreate / RegionUpdate / RegionListParameters types in core-types
• Adds a region module to catalog-driver-sql (list/get/create/update/delete) with entity/domain conversions
• Wires the operations into the CatalogBackend trait and SqlBackend impl
• Adds a RegionNotFound error variant
• Unit tests for each operation using MockDatabase

Reads mirror the existing service/endpoint modules. Create/update/delete follow the patterns used in other SQL drivers.

Closes #723

Note: this contribution was developed with AI assistance

[gtema]

mostly good, but few refinements are still necessary

[mashawes]

Thanks for the review! Addressed all three points. Sorted struct fields and trait/impl methods alphabetically with blank lines between fields, and added validator length limits with max 255 characters taken from the Python region model. Ready for another look.