## Summary

Reduces memory pressure and network payload size by lazy-loading
workflow step execution I/O data instead of fetching it all upfront.


https://github.com/user-attachments/assets/2d77d88d-4017-44bd-8581-082717352921

- **Lazy-load step I/O**: Execution polling (`loadExecutionThunk`) now
requests lightweight data (`includeInput=false`, `includeOutput=false`).
Full step input/output is fetched on demand — when the user clicks a
step's tab or hovers a template expression in the YAML editor.
- **Server-side source filtering**: `getWorkflowExecution` accepts
`includeInput`/`includeOutput` query params and applies
`_source_excludes` on Elasticsearch `mget`/`search` calls, avoiding
large payloads that can cause OOM.
- **Bidirectional React Query cache**: Step I/O fetched by the execution
detail panel (`useStepExecution`) or by the YAML editor hover provider
share a single cache via `queryClient.setQueryData`, preventing
duplicate HTTP requests regardless of access order.
- **Cache cleanup on execution switch**: Cached step data is cleared
(`removeQueries`) when navigating to a different execution, preventing
memory buildup.
- **Template hover priority**: Reordered `provideCustomHover` so
template expression hovers (`{{ }}`) take precedence over validation
decoration tooltips.
- **Pure hover enrichment**: Refactored `ensureStepData` →
`fetchStepDataIfNeeded` to return enriched data instead of mutating the
shared `executionContext` ref. Removed redundant `fetchedStepIds`
tracking that caused a caching bug on repeated hovers.
- **Extracted `useLazyStepExecutionFetcher` hook**: Moved inline fetch
logic out of the YAML editor component into a dedicated hook for
readability and testability.
- **Narrowed memo deps**: `tabs` memo in `WorkflowStepExecutionDetails`
now depends on `hasInput`/`hasError` booleans instead of the full
`stepExecution` object.

### Example flows

**1. Execution polling — lightweight, no I/O**

```
GET /api/workflowExecutions/exec-123?includeInput=false&includeOutput=false
```

Returns execution metadata and step statuses/durations, but `input` and
`output` fields are excluded at the Elasticsearch `_source` level. This
runs every poll cycle.

**2. Hovering a template expression — lazy fetch + cache**

User hovers `{{ steps.search.output.hits }}` in the YAML editor:

```
1. Hover provider calls fetchStepExecutionData("search")
2. Hook maps "search" → step doc ID "step-doc-abc"
3. React Query cache miss → GET /api/workflowExecutions/exec-123/steps/step-doc-abc
4. Response stored in cache: queryClient.setQueryData(["stepExecution", "exec-123", "step-doc-abc"], data)
5. Hover tooltip shows the resolved value

Second hover on the same step (or any steps.search.* expression):
1. fetchStepExecutionData("search") → cache hit → no HTTP request
2. Hover tooltip shows the resolved value immediately
```

For terminal steps, `useStepExecution` uses `staleTime: Infinity` — the
cached data never goes stale for the lifetime of that execution.

**3. Opening the I/O tab — served from cache**

After the hover above already fetched `step-doc-abc`, user clicks the
step and opens the Output tab:

```
1. useStepExecution("exec-123", "step-doc-abc", "completed") runs
2. React Query finds ["stepExecution", "exec-123", "step-doc-abc"] in cache
3. No HTTP request — data renders immediately
```

This works in both directions: if the user clicks the Output tab first,
the hover provider finds the data in cache on subsequent hovers.

**4. Switching execution — cache cleanup**

```
1. User selects execution "exec-456"
2. useEffect cleanup fires: queryClient.removeQueries({ queryKey: ["stepExecution", "exec-123"] })
3. All cached step I/O for the previous execution is evicted
4. Fresh lightweight polling starts for "exec-456"
```

## Test plan

- [x] `get_workflow_execution.test.ts` — Verifies `_source_excludes` is
correctly passed to `esClient.mget` and `searchStepExecutions` based on
`includeInput`/`includeOutput` flags
- [x] `get_workflow_execution_by_id.test.ts` — Updated existing route
tests; added cases verifying query params are parsed and forwarded to
the API layer
- [x] `use_step_execution.test.ts` — Verifies `staleTime: Infinity` and
no polling for terminal steps; polling at 5s for running steps; polling
stops on status transition
- [x] `workflow_execution_detail.test.tsx` — Verifies `removeQueries` is
called on unmount and when `executionId` changes
- [x] `unified_hover_provider.test.ts` — Verifies hover values persist
across multiple invocations, enrichment skipped when output already
present, graceful fallback when fetch returns null
- [x] `workflow_yaml_editor.test.tsx` — Updated test wrapper to include
`QueryClientProvider` for `useLazyStepExecutionFetcher`

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

…load I/O change (#254087)

## Summary

Fixes workflow execution output retrieval for agent-builder consumers.

After [#253547](#253547) changed
`getWorkflowExecution` to exclude step I/O by default,
`getExecutionState` was no longer receiving step outputs - causing
`getWorkflowOutput` to always return `null`.

This passes `includeOutput: true` explicitly so the output is available
when the execution completes.