Re-level non-docs content to top of repo and rename content→docs

@theme/plugins/index-pages.js

@@ -0,0 +1,63 @@
+// @ts-check
+import { readSharedData } from '@redocly/realm/dist/server/utils/shared-data.js'; // TODO: export function from root package
+const INDEX_PAGE_INFO_DATA_KEY = 'index-page-items';
+
+export function indexPages() {
+  /** @type {import("@redocly/realm/dist/server/plugins/types").PluginInstance } */
+  const instance = {
+    // hook that gets executed after all routes were created
+    async afterRoutesCreated(contentProvider, actions) {
+      // get all the routes that are ind pages
+      const indexRoutes = actions.getAllRoutes().filter(route => route.metadata?.indexPage);
+
+      for (const route of indexRoutes) {
+        // @ts-ignore this uses some internals, we will expose them in nicer way in the future releases
+        const sidebarId = actions.routesSharedData.get(route.slug)?.['sidebar']; // TODO: implement a helper function for this
+        /** @type {any} */
+        const sidebar = await readSharedData(sidebarId, actions.outdir);
+
+        if (!sidebar) {
+          console.log('[warn] Index route used with no sidebar', route.fsPath);
+          continue;
+        }
+
+        const item = findItemDeep(sidebar.items, route.fsPath);
+        const childrenPaths = (item.items || []).map(item => item.fsPath).filter(Boolean);
+
+        const childRoutes = childrenPaths.map(fsPath => actions.getRouteByFsPath(fsPath));
+        const childRoutesData = await Promise.all(
+          childRoutes.map(async route => {
+            const { parsed } = contentProvider.loadContent(route.fsPath, 'frontmatter');
+            return {
+              ...parsed?.data,
+              slug: route.slug,
+              title: await route.getNavText(),
+            };
+          })
+        );
+
+        const sharedDataId = await actions.createSharedData(
+          route.slug + '_' + INDEX_PAGE_INFO_DATA_KEY,
+          childRoutesData
+        );
+        actions.addRouteSharedData(route.slug, INDEX_PAGE_INFO_DATA_KEY, sharedDataId);
+      }
+    },
+  };
+  return instance;
+}
+
+function findItemDeep(items, fsPath) {
+  for (const item of items) {
+    if (item.fsPath === fsPath) {
+      return item;
+    }
+
+    if (item.items) {
+      const found = findItemDeep(item.items, fsPath);
+      if (found) {
+        return found;
+      }
+    }
+  }
+}