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

Snapshots all four versioned Docusaurus sections at v6.1.0, cut from
master after the version-cutting tooling (#39837) and broken-internal-
links fixes (#40102) landed. Captures fresh auto-generated content and
freezes data dependencies so the historical snapshot stays correct.

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.

Snapshot includes:
- All MDX content for the four sections.
- Auto-gen captured fresh: 74 database pages (engine spec metadata),
  ~1,800 API reference files (openapi.json), 59 component pages
  (Storybook stories).
- Data imports frozen at cut time into snapshot-local _versioned_data/
  dirs:
    versioned_docs/version-6.1.0/_versioned_data/src/data/databases.json
      (canonical 80-database diagnostics from master, preserved by the
      generator's input-hash cache)
    admin_docs_versioned_docs/version-6.1.0/_versioned_data/data/countries.json
    admin_docs_versioned_docs/version-6.1.0/_versioned_data/static/feature-flags.json
    developer_docs_versioned_docs/version-6.1.0/_versioned_data/static/data/components.json
- Import paths in deeply-nested files rewritten so they still resolve
  from one directory deeper inside the snapshot.

Verified via full yarn build: exit 0, no broken links surfaced by
onBrokenLinks: throw. Anchor warnings present are pre-existing on
master (community#superset-community-calendar) and unrelated.

docs/developer_docs_versioned_docs/version-6.1.0/api/schemas/chartdataadhocmetricschema.Schema.json

@@ -0,0 +1 @@
+{"schema":{"properties":{"aggregate":{"description":"Aggregation operator.Only required for simple expression types.","enum":["AVG","COUNT","COUNT_DISTINCT","MAX","MIN","SUM"],"type":"string"},"column":{"properties":{"column_name":{"description":"The name of the target column","example":"mycol","type":"string"},"type":{"description":"Type of target column","example":"BIGINT","type":"string"}},"type":"object","title":"ChartDataColumn"},"expressionType":{"description":"Simple or SQL metric","enum":["SIMPLE","SQL"],"example":"SQL","type":"string"},"hasCustomLabel":{"description":"When false, the label will be automatically generated based on the aggregate expression. When true, a custom label has to be specified.","example":true,"type":"boolean"},"isExtra":{"description":"Indicates if the filter has been added by a filter component as opposed to being a part of the original query.","type":"boolean"},"label":{"description":"Label for the metric. Is automatically generated unlesshasCustomLabel is true, in which case label must be defined.","example":"Weighted observations","type":"string"},"optionName":{"description":"Unique identifier. Can be any string value, as long as all metrics have a unique identifier. If undefined, a random namewill be generated.","example":"metric_aec60732-fac0-4b17-b736-93f1a5c93e30","type":"string"},"sqlExpression":{"description":"The metric as defined by a SQL aggregate expression. Only required for SQL expression type.","example":"SUM(weight * observations) / SUM(weight)","type":"string"},"timeGrain":{"description":"Optional time grain for temporal filters","example":"PT1M","type":"string"}},"required":["expressionType"],"type":"object","title":"ChartDataAdhocMetricSchema"},"schemaType":"response"}