Merge pull request #27003 from backstage/rugvip/preserve

cli: use preserveModules for CJS builds

.changeset/angry-cycles-call.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Preserve directory structure for CommonJS build output, just like ESM. This makes the build output more stable and easier to browse, and allows for more effective tree shaking and lazy imports.

packages/cli/src/lib/builder/config.ts

@@ -123,6 +123,8 @@ export async function makeRollupConfigs(
         format: 'commonjs',
         interop: 'compat',
         sourcemap: true,
+        preserveModules: true,
+        preserveModulesRoot: `${targetDir}/src`,
         exports: 'named',
       });
     }