Add store settings page with location management

Company table gains address and logo_file_id columns. New store
settings API: GET/PATCH /store for company info, full CRUD for
/locations. Settings page shows store name, phone, email, address,
timezone with inline edit. Location cards with add/edit/delete.
Settings link in admin sidebar. Fixes leftover company_id on
location table and seed files.

packages/backend/src/db/migrations/0023_store_settings.sql

@@ -0,0 +1,6 @@
+-- Add address and logo to company (store settings)
+ALTER TABLE "company" ADD COLUMN IF NOT EXISTS "address" jsonb;
+ALTER TABLE "company" ADD COLUMN IF NOT EXISTS "logo_file_id" uuid REFERENCES "file"("id");
+
+-- Drop leftover company_id from location (missed in 0021)
+ALTER TABLE "location" DROP COLUMN IF EXISTS "company_id";