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/schemas/dashboarddatasetschema.schema.mdx

@@ -0,0 +1,31 @@
+---
+id: dashboarddatasetschema
+title: "DashboardDatasetSchema"
+description: ""
+sidebar_label: "DashboardDatasetSchema"
+hide_title: true
+hide_table_of_contents: true
+schema: true
+sample: {"always_filter_main_dttm":true,"cache_timeout":0,"column_formats":{},"column_names":["string"],"column_types":[0],"columns":[{}],"currency_code_column":"string","database":{"allow_multi_catalog":true,"allows_cost_estimate":true,"allows_subquery":true,"allows_virtual_table_explore":true,"backend":"string","disable_data_preview":true,"disable_drill_to_detail":true,"explore_database_id":0,"id":0,"name":"string"},"datasource_name":"string","default_endpoint":"string","edit_url":"string","fetch_values_predicate":"string","filter_select":true,"filter_select_enabled":true,"granularity_sqla":["string"],"health_check_message":"string","id":0,"is_sqllab_view":true,"main_dttm_col":"string","metrics":[{}],"name":"string","normalize_columns":true,"offset":0,"order_by_choices":["string"],"owners":[{}],"params":"string","perm":"string","schema":"string","select_star":"string","sql":"string","table_name":"string","template_params":"string","time_grain_sqla":["string"],"type":"string","uid":"string","verbose_map":{}}
+custom_edit_url: null
+---
+
+import Schema from "@theme/Schema";
+import Heading from "@theme/Heading";
+
+<Heading
+  as={"h1"}
+  className={"openapi__heading"}
+  children={"DashboardDatasetSchema"}
+>
+</Heading>
+
+
+
+
+
+<Schema
+  {...require("./dashboarddatasetschema.Schema.json")}
+>
+
+</Schema>