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/contributing/pkg-resources-migration.md

@@ -0,0 +1,94 @@
+---
+title: pkg_resources Migration Guide
+sidebar_position: 9
+---
+
+<!--
+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.
+-->
+
+# pkg_resources Deprecation and Migration Guide
+
+## Background
+
+As of setuptools 81.0.0, the `pkg_resources` API is deprecated and will be removed. This affects several packages in the Python ecosystem.
+
+## Current Status
+
+### Superset Codebase
+
+The Superset codebase has already migrated away from `pkg_resources` to the modern `importlib.metadata` API:
+
+- `superset/db_engine_specs/__init__.py` - Uses `from importlib.metadata import entry_points`
+- All entry point loading uses the modern API
+
+### Production Dependencies
+
+Some third-party dependencies may still use `pkg_resources`. Monitor your dependency tree for packages that haven't migrated yet.
+
+## Migration Path
+
+### Short-term Solution
+
+Pin setuptools to version 80.x to prevent breaking changes:
+
+```python
+# requirements/base.in
+setuptools<81
+```
+
+This prevents the removal of `pkg_resources` while dependent packages are updated.
+
+### Long-term Solution
+
+Update all dependencies to use `importlib.metadata` instead of `pkg_resources`:
+
+#### Migration Example
+
+**Old (deprecated):**
+```python
+import pkg_resources
+
+version = pkg_resources.get_distribution("package_name").version
+entry_points = pkg_resources.iter_entry_points("group_name")
+```
+
+**New (recommended):**
+```python
+from importlib.metadata import version, entry_points
+
+pkg_version = version("package_name")
+eps = entry_points(group="group_name")
+```
+
+## Action Items
+
+### For Superset Maintainers
+1. The Superset codebase already uses `importlib.metadata`
+2. Monitor third-party dependencies for updates
+3. Update setuptools pin once the ecosystem is ready
+
+### For Extension Developers
+1. **Update your packages** to use `importlib.metadata` instead of `pkg_resources`
+2. **Test with setuptools >= 81.0.0** once all packages are migrated
+
+## References
+
+- [setuptools pkg_resources deprecation notice](https://setuptools.pypa.io/en/latest/pkg_resources.html)
+- [importlib.metadata documentation](https://docs.python.org/3/library/importlib.metadata.html)
+- [Migration guide](https://setuptools.pypa.io/en/latest/deprecated/pkg_resources.html)