refactor(csv-loader): simplify module generation logic

Update the code generation in `csvToModule` to use a more concise
mapping pattern for row resolvers, removing the unnecessary object
spread and nested braces.

src/csv-loader/module-gen.ts

@@ -233,10 +233,9 @@ export function csvToModule(
     ...reverseLookupInits.map((l) => `  ${l}`),
     ...(rowResolvers.length > 0
       ? [
-          "  _resolved = _raw.map(row => ({",
-          "    ...row,",
-          ...rowResolvers,
-          "  }));",
+          "  _resolved = _raw.map(row => (",
+          ...rowResolvers.map((r) => `    row${r.slice(1)}`),
+          "    row));",
         ]
       : []),
     "  return _resolved;",