Refactor roles management to use role code as primary key

- Updated the roles table schema to use role code as the primary key, enhancing readability in junction tables.
- Modified related tables (user_roles, product_role_visibility) to reference role code instead of role ID.
- Adjusted seeding logic and utility functions to accommodate the new primary key structure, ensuring consistent role management across the application.
- Added a migration script to facilitate the database schema changes.

server/database/migrations/meta/_journal.json

@@ -15,6 +15,13 @@
       "when": 1762074397305,
       "tag": "0001_clammy_bulldozer",
       "breakpoints": true
+    },
+    {
+      "idx": 2,
+      "version": "7",
+      "when": 1762157410000,
+      "tag": "0002_refactor_roles_primary_key",
+      "breakpoints": true
     }
   ]
 }