feat(items): add food category to item usage options

Update items table CHECK constraint to allow 'food' usage_key
Add 'food' to itemUsageOptions in backend queries with translations
Update design documentation to include the new category

backend/db/schema.sql

@@ -1214,7 +1214,7 @@ CREATE TABLE IF NOT EXISTS items (
     ancient_artifact_category_key IS NULL
     OR ancient_artifact_category_key IN ('lost-relics-l', 'lost-relics-s', 'fossils')
   ),
-  CHECK (usage_key IS NULL OR usage_key IN ('decoration', 'relaxation', 'toy', 'road'))
+  CHECK (usage_key IS NULL OR usage_key IN ('decoration', 'relaxation', 'toy', 'road', 'food'))
 );
 
 CREATE TABLE IF NOT EXISTS recipes (