Add a codemod for transforming configs to the new format

packages/steiger/migrations/transform-config.js

@@ -0,0 +1,46 @@
+/** @type {import('jscodeshift').Transform} */
+export default function transformer(file, api) {
+  const j = api.jscodeshift
+  const root = j(file.source)
+
+  // Add "fsd/" prefix to FSD rule names
+  root
+    .find(j.Literal)
+    .filter((path) => ruleNames.includes(path.node.value))
+    .replaceWith((path) => j.stringLiteral(`fsd/${path.node.value}`))
+
+  // Make the default export or the argument of `defineConfig` an array
+  const defineConfigCalls = root.find(j.CallExpression).filter((path) => path.node.callee.name === 'defineConfig')
+
+  if (defineConfigCalls.length > 0) {
+    defineConfigCalls
+      .find(j.ObjectExpression)
+      .at(0)
+      .replaceWith((path) => j.arrayExpression([path.value]))
+  } else {
+    root.find(j.ExportDefaultDeclaration).forEach((path) => {
+      path.value.declaration = j.arrayExpression([path.value.declaration])
+    })
+  }
+
+  return root.toSource()
+}
+
+const ruleNames = [
+  'ambiguous-slice-names',
+  'excessive-slicing',
+  'forbidden-imports',
+  'inconsistent-naming',
+  'insignificant-slice',
+  'no-layer-public-api',
+  'no-public-api-sidestep',
+  'no-reserved-folder-names',
+  'no-segmentless-slices',
+  'no-segments-on-sliced-layers',
+  'public-api',
+  'repetitive-naming',
+  'segments-by-purpose',
+  'shared-lib-grouping',
+  'no-processes',
+  'import-locality',
+]