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

- Snapshot all four versioned docs sections at v6.1.0; master continues to
  serve as "Next" (lastVersion: current, banner: unreleased) so editing
  master keeps updating the canonical URLs
- Enable the previously-disabled components plugin and version it
- Rename stale "developer_portal" references to "developer_docs" across
  package.json scripts, manage-versions.mjs, theme files (DocVersionBadge,
  DocVersionBanner), DOCS_CLAUDE.md, and README.md (URL backward-compat
  redirect /developer_portal/* preserved)
- Add admin_docs version scripts; drop dead "tutorials" plugin id from
  the version badge
- Generalize fixVersionedImports in manage-versions.mjs to walk every
  section's snapshot and rewrite ../../src/ and ../../data/ imports,
  catching admin_docs and components files that previous version cuts
  would have broken
- Remove orphan files: developer_portal_versions.json,
  tutorials_versions.json, and stray empty versions.json files inside
  components/ and developer_docs/ content directories

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

@@ -0,0 +1 @@
+{"schema":{"properties":{"always_filter_main_dttm":{"type":"boolean"},"cache_timeout":{"type":"integer"},"column_formats":{"type":"object"},"column_names":{"items":{"type":"string"},"type":"array"},"column_types":{"items":{"type":"integer"},"type":"array"},"columns":{"items":{"type":"object"},"type":"array"},"database":{"properties":{"allow_multi_catalog":{"type":"boolean"},"allows_cost_estimate":{"type":"boolean"},"allows_subquery":{"type":"boolean"},"allows_virtual_table_explore":{"type":"boolean"},"backend":{"type":"string"},"disable_data_preview":{"type":"boolean"},"disable_drill_to_detail":{"type":"boolean"},"explore_database_id":{"type":"integer"},"id":{"type":"integer"},"name":{"type":"string"}},"type":"object","title":"Database"},"datasource_name":{"type":"string"},"default_endpoint":{"type":"string"},"edit_url":{"type":"string"},"fetch_values_predicate":{"type":"string"},"filter_select":{"type":"boolean"},"filter_select_enabled":{"type":"boolean"},"granularity_sqla":{"items":{"items":{"type":"string"},"type":"array"},"type":"array"},"health_check_message":{"type":"string"},"id":{"type":"integer"},"is_sqllab_view":{"type":"boolean"},"main_dttm_col":{"type":"string"},"metrics":{"items":{"type":"object"},"type":"array"},"name":{"type":"string"},"normalize_columns":{"type":"boolean"},"offset":{"type":"integer"},"order_by_choices":{"items":{"items":{"type":"string"},"type":"array"},"type":"array"},"owners":{"items":{"type":"object"},"type":"array"},"params":{"type":"string"},"perm":{"type":"string"},"schema":{"type":"string"},"select_star":{"type":"string"},"sql":{"type":"string"},"table_name":{"type":"string"},"template_params":{"type":"string"},"time_grain_sqla":{"items":{"items":{"type":"string"},"type":"array"},"type":"array"},"type":{"type":"string"},"uid":{"type":"string"},"verbose_map":{"additionalProperties":{"type":"string"},"type":"object"}},"type":"object","title":"DashboardDatasetSchema"},"schemaType":"response"}