feat(docs): migrate documentation site into monorepo (#5912)

apps/docs/plugins/validate-docs-coverage.ts

@@ -0,0 +1,38 @@
+import type { LoadContext, Plugin } from "@docusaurus/types";
+import fs from "node:fs";
+import path from "node:path";
+
+import { integrationDocSlugs } from "@homarr/definitions/docs/integration-doc-slugs";
+import { widgetDocSlugs } from "@homarr/definitions/docs/widget-doc-slugs";
+
+const slugMaps = {
+  Integration: { slugs: integrationDocSlugs, folder: "integrations" },
+  Widget: { slugs: widgetDocSlugs, folder: "widgets" },
+} as const;
+
+export default function validateDocsCoveragePlugin(context: LoadContext): Plugin {
+  return {
+    name: "validate-docs-coverage",
+    async loadContent() {
+      const docsDir = path.resolve(context.siteDir, "docs");
+      const missing: string[] = [];
+
+      for (const [label, { slugs, folder }] of Object.entries(slugMaps)) {
+        for (const [kind, slug] of Object.entries(slugs)) {
+          if (!slug) continue;
+          if (!fs.existsSync(path.join(docsDir, folder, slug))) {
+            missing.push(`${label} "${kind}" -> docs/${folder}/${slug}/`);
+          }
+        }
+      }
+
+      if (missing.length > 0) {
+        throw new Error(
+          `Missing documentation for ${missing.length} feature(s):\n` +
+            missing.map((m) => `  - ${m}`).join("\n") +
+            "\n\nCreate the missing doc folders with index.ts + index.mdx.",
+        );
+      }
+    },
+  };
+}