cli: include root package in schema search + update docs

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/good-cars-confess.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Configuration schema is now also collected from the root `package.json` if it exists.

docs/conf/defining.md

@@ -13,9 +13,10 @@ which during validation is stitched together into a single schema.
 ## Schema Collection and Definition
 
 Schemas are collected from all packages and dependencies in each repo that are a
-part of the Backstage ecosystem, including transitive dependencies. The current
-definition of "part of the ecosystem" is that a package has at least one
-dependency in the `@backstage` namespace, but this is subject to change.
+part of the Backstage ecosystem, including the root package and transitive
+dependencies. The current definition of "part of the ecosystem" is that a
+package has at least one dependency in the `@backstage` namespace or a
+`"configSchema"` field in `package.json`, but this is subject to change.
 
 Each package is searched for a schema at a single point of entry, a top-level
 `"configSchema"` field in `package.json`. The field can either contain an

packages/cli/src/lib/config.ts

@@ -39,6 +39,8 @@ export async function loadCliConfig(options: Options) {
 
   const schema = await loadConfigSchema({
     dependencies: localPackageNames,
+    // Include the package.json in the project root if it exists
+    packagePaths: [paths.resolveTargetRoot('package.json')],
   });
 
   const appConfigs = await loadConfig({