docs: cut 6.1.0 versions for docs, admin_docs, developer_docs, components

Snapshots all four versioned Docusaurus sections at v6.1.0. Built on
top of the version-cutting tooling work in chore/docs-cut-6.1.0-versions
so the snapshot benefits from:

- Auto-gen refresh before snapshotting (database pages from engine
  spec metadata, API reference from openapi.json, component pages
  from Storybook stories) — captured at the SHA we cut from rather
  than whatever happened to be on disk.
- Data-import freeze: country list, feature flag table, database
  diagnostics, and component metadata are copied into snapshot-local
  `_versioned_data/` dirs so the historical version doesn't silently
  mutate when the source files change.
- Depth-aware import-path rewriter that handles deeply-nested
  component MDX files referencing `../../../src/` from the snapshot.

Versioning behavior: `lastVersion` stays at `current` for every
section, so the canonical URLs (`/docs/...`, `/admin-docs/...`,
`/developer-docs/...`, `/components/...`) continue to render content
from master. The `current` version is consistently labeled "Next"
with an `unreleased` banner, and `6.1.0` is a historical pin
accessible only via its explicit version segment.

Component playground: previously `disabled: true` in versions-config.json,
now enabled and versioned. The plugin block in docusaurus.config.ts
was already gated only by the `disabled` flag, so no other code
changes were needed to bring it back online.

The frozen `databases.json` in the snapshot is the canonical 80-database
artifact from the latest committed state in master (preserved by the
generator's input-hash cache), not a fallback regenerated from a
local Flask environment.

docs/developer_docs_versioned_docs/version-6.1.0/testing/storybook.md

@@ -0,0 +1,114 @@
+---
+title: Storybook
+sidebar_position: 5
+---
+
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you 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.
+-->
+
+# Storybook
+
+Superset uses [Storybook](https://storybook.js.org/) for developing and testing UI components in isolation. Storybook provides a sandbox to build components independently, outside of the main application.
+
+## Public Storybook
+
+A public Storybook with components from the `master` branch is available at:
+
+**[apache-superset.github.io/superset-ui](https://apache-superset.github.io/superset-ui/?path=/story/*)**
+
+## Running Locally
+
+### Main Superset Storybook
+
+To run the main Superset Storybook locally:
+
+```bash
+cd superset-frontend
+
+# Start Storybook (opens at http://localhost:6006)
+npm run storybook
+
+# Build static Storybook
+npm run build-storybook
+```
+
+### @superset-ui Package Storybook
+
+The `@superset-ui` packages have a separate Storybook for component library development:
+
+```bash
+cd superset-frontend
+
+# Install dependencies and bootstrap packages
+npm ci && npm run bootstrap
+
+# Start the @superset-ui Storybook (opens at http://localhost:9001)
+cd packages/superset-ui-demo
+npm run storybook
+```
+
+## Adding Stories
+
+### To an Existing Package
+
+If stories already exist for the package, extend the `examples` array in the package's story file:
+
+```
+storybook/stories/<package>/index.js
+```
+
+### To a New Package
+
+1. Add package dependencies:
+
+   ```bash
+   npm install <package>
+   ```
+
+2. Create a story folder matching the package name:
+
+   ```bash
+   mkdir storybook/stories/superset-ui-<package>/
+   ```
+
+3. Create an `index.js` file with the story configuration:
+
+   ```javascript
+   export default {
+     examples: [
+       {
+         storyPath: '@superset-ui/package',
+         storyName: 'My Story',
+         renderStory: () => <MyComponent />,
+       },
+     ],
+   };
+   ```
+
+   Use the `|` separator for nested stories:
+   ```javascript
+   storyPath: '@superset-ui/package|Category|Subcategory'
+   ```
+
+## Best Practices
+
+- **Isolate components**: Stories should render components in isolation, without application context
+- **Show variations**: Create stories for different states, sizes, and configurations
+- **Document props**: Use Storybook's controls to expose configurable props
+- **Test edge cases**: Include stories for loading states, error states, and empty states