docs: cut 6.1.0 versions for user_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), broken-internal-
links fix (#40102), and user_docs rename (#40171) all landed. With
the rename in place, all four sections now produce parallel-named
files at the docs/ root (no more bare `versioned_docs/` outlier).

Versioning behavior: lastVersion stays at current for every section,
so the canonical URLs (/user-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.

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:
    user_docs_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.
- developer_docs/extensions/overview.md snapshot has the FIXED
  ./mcp.md form (from #40102), so the SPA-nav 404 isn't baked into
  the 6.1.0 version.

Verified via full yarn build: exit 0, no broken links surfaced by
onBrokenLinks: throw.

docs/developer_docs_versioned_docs/version-6.1.0/api/schemas/dashboardrestapi-put.Schema.json

@@ -0,0 +1 @@
+{"schema":{"properties":{"certification_details":{"description":"Details of the certification","nullable":true,"type":"string"},"certified_by":{"description":"Person or group that has certified this dashboard","nullable":true,"type":"string"},"css":{"description":"Override CSS for the dashboard.","nullable":true,"type":"string"},"dashboard_title":{"description":"A title for the dashboard.","maxLength":500,"minLength":0,"nullable":true,"type":"string"},"external_url":{"nullable":true,"type":"string"},"is_managed_externally":{"nullable":true,"type":"boolean"},"json_metadata":{"description":"This JSON object is generated dynamically when clicking the save or overwrite button in the dashboard view. It is exposed here for reference and for power users who may want to alter  specific parameters.","nullable":true,"type":"string"},"owners":{"items":{"description":"Owner are users ids allowed to delete or change this dashboard. If left empty you will be one of the owners of the dashboard.","nullable":true,"type":"integer"},"type":"array"},"position_json":{"description":"This json object describes the positioning of the widgets in the dashboard. It is dynamically generated when adjusting the widgets size and positions by using drag & drop in the dashboard view","nullable":true,"type":"string"},"published":{"description":"Determines whether or not this dashboard is visible in the list of all dashboards.","nullable":true,"type":"boolean"},"roles":{"items":{"description":"Roles is a list which defines access to the dashboard. These roles are always applied in addition to restrictions on dataset level access. If no roles defined then the dashboard is available to all roles.","nullable":true,"type":"integer"},"type":"array"},"slug":{"description":"Unique identifying part for the web address of the dashboard.","maxLength":255,"minLength":0,"nullable":true,"type":"string"},"tags":{"items":{"description":"Tags to be associated with the dashboard","nullable":true,"type":"integer"},"type":"array"},"theme_id":{"description":"Theme ID for the dashboard","nullable":true,"type":"integer"},"uuid":{"format":"uuid","nullable":true,"type":"string"}},"type":"object","title":"DashboardRestApi.put"},"schemaType":"response"}