[kibana-type-check-analysis] Kibana type check: spec fixes needed

Build: (buildkite.com/redacted) ## Analysis ### SPEC errors (5 errors) — root cause: missing `max_retention` in `RetentionSource` enum The `RetentionSource` enum in `specification/indices/_types/DataStreamLifecycle.ts` is missing the `max_retention` value. Elasticsearch returns `"max_retention"` as a valid `retention_determined_by` value when the data stream's effective retention is capped by the global `max_retention` setting (`GlobalRetention.max_retention`), but the spec enum only defines: ```typescript export enum RetentionSource { data_stream_configuration, default_global_retention, max_global_retention, default_failures_retention } ``` Kibana code in multiple files uses `retention_determined_by: "max_retention"` against the generated client type, causing TypeScript to reject it as outside the known union. **Required fix:** Add `max_retention` to the `RetentionSource` enum in `specification/indices/_types/DataStreamLifecycle.ts`. **Affected Kibana files:** - `x-pack/platform/plugins/shared/index_management/__jest__/client_integration/home/data_streams_project_level_retention.test.ts:57` — TS2322: `'"max_retention"'` not assignable to `RetentionSource | undefined` - `x-pack/platform/plugins/shared/index_management/__jest__/client_integration/home/data_streams_tab.test.ts:216` — same TS2322 - `x-pack/platform/plugins/shared/index_management/public/application/sections/home/data_stream_list/data_stream_table/data_stream_table.test.tsx:241` — TS2352: object literal with `retention_determined_by: "max_retention"` cannot be cast - `x-pack/platform/plugins/shared/index_management/public/application/sections/home/data_stream_list/data_stream_table/data_stream_table.test.tsx:269` — same TS2352 - `x-pack/platform/plugins/shared/index_management/public/application/sections/home/data_stream_list/data_stream_table/data_stream_table.tsx:264` — TS2367: comparison `retention_determined_by === "max_retention"` has no overlap with the narrowed enum type --- ### Non-SPEC errors (for reference) The remaining 3 errors are classified as **KIBANA** and do not require spec changes: - `server/routes/api/data_streams/register_get_route.ts:192` and `:271` — TS2322: `Duration | undefined` (= `string | -1 | 0 | undefined`) not assignable to `string | undefined`. Kibana's internal response type uses `string` for `frozen_after` but the spec correctly types it as `Duration`. Kibana needs to widen its local type or cast the value. - `server/lib/data_stream_serialization.ts:125` — TS2322: partially a downstream effect of the same `Duration`/`frozen_after` mismatch in Kibana's `IndicesDataStreamLifecycleWithRollover` augmentation type. > Generated by [Kibana type check analysis](https://github.com/elastic/elasticsearch-specification/actions/runs/26647864243) · ● 1.6M · [◷](https://github.com/search?q=repo%3Aelastic%2Felasticsearch-specification+is%3Aissue+%22gh-aw-workflow-call-id%3A+elastic%2Felasticsearch-specification%2Fkibana-type-check-analysis%22&type=issues) <!-- gh-aw-agentic-workflow: Kibana type check analysis, engine: claude, model: llm-gateway/claude-sonnet-4-6, id: 26647864243, workflow_id: kibana-type-check-analysis, run: https://github.com/elastic/elasticsearch-specification/actions/runs/26647864243 --> <!-- gh-aw-workflow-id: kibana-type-check-analysis --> <!-- gh-aw-workflow-call-id: elastic/elasticsearch-specification/kibana-type-check-analysis -->