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

- Snapshot all four versioned docs sections at v6.1.0; master continues to
  serve as "Next" (lastVersion: current, banner: unreleased) so editing
  master keeps updating the canonical URLs
- Enable the previously-disabled components plugin and version it
- Rename stale "developer_portal" references to "developer_docs" across
  package.json scripts, manage-versions.mjs, theme files (DocVersionBadge,
  DocVersionBanner), DOCS_CLAUDE.md, and README.md (URL backward-compat
  redirect /developer_portal/* preserved)
- Add admin_docs version scripts; drop dead "tutorials" plugin id from
  the version badge
- Generalize fixVersionedImports in manage-versions.mjs to walk every
  section's snapshot and rewrite ../../src/ and ../../data/ imports,
  catching admin_docs and components files that previous version cuts
  would have broken
- Remove orphan files: developer_portal_versions.json,
  tutorials_versions.json, and stray empty versions.json files inside
  components/ and developer_docs/ content directories

docs/developer_docs_versioned_docs/version-6.1.0/components/ui/index.mdx

@@ -0,0 +1,77 @@
+---
+title: Core Components
+sidebar_label: Core Components
+sidebar_position: 1
+---
+
+<!--
+    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.
+-->
+
+# Core Components
+
+46 components available in this category.
+
+## Components
+
+- [AutoComplete](./autocomplete)
+- [Avatar](./avatar)
+- [Badge](./badge)
+- [Breadcrumb](./breadcrumb)
+- [Button](./button)
+- [ButtonGroup](./buttongroup)
+- [CachedLabel](./cachedlabel)
+- [Card](./card)
+- [Checkbox](./checkbox)
+- [Collapse](./collapse)
+- [DatePicker](./datepicker)
+- [Divider](./divider)
+- [EditableTitle](./editabletitle)
+- [EmptyState](./emptystate)
+- [FaveStar](./favestar)
+- [IconButton](./iconbutton)
+- [Icons](./icons)
+- [IconTooltip](./icontooltip)
+- [InfoTooltip](./infotooltip)
+- [Input](./input)
+- [Label](./label)
+- [List](./list)
+- [ListViewCard](./listviewcard)
+- [Loading](./loading)
+- [Menu](./menu)
+- [Modal](./modal)
+- [ModalTrigger](./modaltrigger)
+- [Popover](./popover)
+- [ProgressBar](./progressbar)
+- [Radio](./radio)
+- [SafeMarkdown](./safemarkdown)
+- [Select](./select)
+- [Skeleton](./skeleton)
+- [Slider](./slider)
+- [Steps](./steps)
+- [Switch](./switch)
+- [TableCollection](./tablecollection)
+- [TableView](./tableview)
+- [Tabs](./tabs)
+- [Timer](./timer)
+- [Tooltip](./tooltip)
+- [Tree](./tree)
+- [TreeSelect](./treeselect)
+- [Typography](./typography)
+- [UnsavedChangesModal](./unsavedchangesmodal)
+- [Upload](./upload)