Adds PATCH and DELETE endpoints for brands and shops that mirror the
existing bins pattern: deleting a brand or shop nullifies referencing
products (and strains, for brands) inside a transaction so nothing is
lost. Brand renames return 409 when the new name collides with the
UNIQUE constraint, surfaced inline in the edit modal.
The Brands and Shops views now show inline edit/trash icons on each
card; the trash button confirms with a preview of how many products
will be unparented.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
josh