fix: used forked repo as default, not upstream

Tested with `node ./bin/gh.mjs template-oss-fix --install --filter 'name:json-parse-even-better-errors'` after removing `~/projects/npm/json-parse-even-better-errors`

lib/gh/workers/_common.mjs

@@ -15,6 +15,11 @@ export const clone = ({ argv, item }) => [
         status === 1 && output.includes('already exists') && 0,
     },
   ],
+  // choose the forked repo as the default, for operations like template-oss-fix
+  // See https://github.com/cli/cli/issues/9261#issuecomment-2193936803
+  [ 'gh',
+    ['repo', 'set-default', `${item.owner}/${item.name}`],
+  ]
 ]
 
 export const checkout = ({ argv }) => [