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/chartdataextras.Schema.json

@@ -0,0 +1 @@
+{"schema":{"properties":{"column_order":{"description":"Ordered list of column names for result ordering. Used to preserve user's column reordering (including mixed dimension columns and metrics)","items":{"type":"string"},"nullable":true,"type":"array"},"having":{"description":"HAVING clause to be added to aggregate queries using AND operator.","type":"string"},"instant_time_comparison_range":{"description":"This is only set using the new time comparison controls that is made available in some plugins behind the experimental feature flag.","nullable":true,"type":"string"},"relative_end":{"description":"End time for relative time deltas. Default: `config[\"DEFAULT_RELATIVE_START_TIME\"]`","enum":["today","now"],"type":"string"},"relative_start":{"description":"Start time for relative time deltas. Default: `config[\"DEFAULT_RELATIVE_START_TIME\"]`","enum":["today","now"],"type":"string"},"time_grain_sqla":{"description":"To what level of granularity should the temporal column be aggregated. Supports [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601#Durations) durations.","enum":["PT1S","PT5S","PT30S","PT1M","PT5M","PT10M","PT15M","PT30M","PT1H","PT6H","P1D","P1W","P1M","P3M","P1Y","1969-12-28T00:00:00Z/P1W","1969-12-29T00:00:00Z/P1W","P1W/1970-01-03T00:00:00Z","P1W/1970-01-04T00:00:00Z",null],"example":"P1D","nullable":true,"type":"string"},"transpile_to_dialect":{"description":"If true, WHERE/HAVING clauses will be transpiled to the target database dialect using SQLGlot.","nullable":true,"type":"boolean"},"where":{"description":"WHERE clause to be added to queries using AND operator.","type":"string"}},"type":"object","title":"ChartDataExtras"},"schemaType":"response"}