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/api/create-a-theme.api.mdx

@@ -0,0 +1,66 @@
+---
+id: create-a-theme
+title: "Create a theme"
+description: "Create a theme"
+sidebar_label: "Create a theme"
+hide_title: true
+hide_table_of_contents: true
+api: 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
+sidebar_class_name: "post api-method"
+info_path: developer-docs/api/superset
+custom_edit_url: null
+hide_send_button: true
+show_extensions: true
+---
+
+import MethodEndpoint from "@theme/ApiExplorer/MethodEndpoint";
+import ParamsDetails from "@theme/ParamsDetails";
+import RequestSchema from "@theme/RequestSchema";
+import StatusCodes from "@theme/StatusCodes";
+import OperationTabs from "@theme/OperationTabs";
+import TabItem from "@theme/TabItem";
+import Heading from "@theme/Heading";
+import Translate from "@docusaurus/Translate";
+
+<Heading
+  as={"h1"}
+  className={"openapi__heading"}
+  children={"Create a theme"}
+>
+</Heading>
+
+<MethodEndpoint
+  method={"post"}
+  path={"/api/v1/theme/"}
+  context={"endpoint"}
+>
+
+</MethodEndpoint>
+
+
+
+Create a theme
+
+<Heading
+  id={"request"}
+  as={"h2"}
+  className={"openapi-tabs__heading"}
+>
+  <Translate id="theme.openapi.request.title">Request</Translate>
+</Heading>
+
+<ParamsDetails>
+
+</ParamsDetails>
+
+<RequestSchema
+  {...require("./create-a-theme.RequestSchema.json")}
+>
+
+</RequestSchema>
+
+<StatusCodes
+  {...require("./create-a-theme.StatusCodes.json")}
+>
+
+</StatusCodes>