repo: promote app-next to main example app

This renames packages to make the new frontend system the default:

- packages/app → packages/app-legacy (example-app-legacy)
- packages/app-next → packages/app (example-app)
- packages/app-next-example-plugin → packages/app-example-plugin

Updated all related configuration, scripts, and documentation.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

packages/app-example-plugin/src/Component.tsx

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export const Component = () => (
+  <div>
+    <h1>SHIP IT!</h1>
+  </div>
+);

packages/app-example-plugin/src/ExampleSidebarItem.tsx

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { SidebarItem } from '@backstage/core-components';
+import SaveIcon from '@material-ui/icons/Save';
+
+/** @public */
+export const ExampleSidebarItem = () => (
+  <SidebarItem text="Example" to="/example" icon={SaveIcon} />
+);

packages/app-example-plugin/src/index.ts

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export { examplePlugin as default } from './plugin';
+
+// TODO: This should be an extension created & exported in the `plugin.tsx`
+export { ExampleSidebarItem } from './ExampleSidebarItem';

packages/app-example-plugin/src/plugin.tsx

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  PageBlueprint,
+  createFrontendPlugin,
+} from '@backstage/frontend-plugin-api';
+
+export const ExamplePage = PageBlueprint.make({
+  params: {
+    path: '/example',
+    loader: () => import('./Component').then(m => <m.Component />),
+  },
+});
+
+/** @public */
+export const examplePlugin = createFrontendPlugin({
+  pluginId: 'example',
+  extensions: [ExamplePage],
+});