[ux-design-patrol] Streaming docs mix preview page with GA applies_to marker

Recent commits have introduced UI/UX patterns that diverge from established patterns elsewhere in the codebase. The following inconsistency reduces design consistency for users.

## Design Drift Findings

### 1. `filebeat-input-streaming` mixes preview and GA lifecycle markers on the same page

**Commit(s):** [2e9f4a2d61bfca85cffadffcee926beefa125fa8](https://github.com/elastic/beats/commit/2e9f4a2d61bfca85cffadffcee926beefa125fa8)

**New pattern (introduced by commit):**
```text
{applies_to}`stack: ga 9.4+` The CrowdStrike discover endpoint can return multiple feed resources...
```

**Existing pattern (established elsewhere):**
```text
applies_to:
stack: preview
serverless: preview

This functionality is in technical preview and may be changed or removed...
```

**Location of new pattern:** `docs/reference/filebeat/filebeat-input-streaming.md:59`

**Location of existing pattern:**
- `docs/reference/filebeat/filebeat-input-streaming.md:1-7`
- `docs/reference/filebeat/filebeat-input-streaming.md:12-13`

**User impact:** The same page simultaneously presents the input as technical preview and a newly added section as GA (`stack: ga 9.4+`). Users can misread maturity/support status and rollout guidance for the same feature area.

## Suggested Actions

- [ ] Align lifecycle markers in `docs/reference/filebeat/filebeat-input-streaming.md` so CrowdStrike guidance uses the same maturity designation as the page (or move GA-only guidance to a page/section with consistent GA framing).

---
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> - [x] expires on Sep 18, 2026, 1:13 PM UTC

Start with docs/reference/filebeat/filebeat-input-streaming.md, especially lines 1-13 and 59, and compare the page-level preview marker with the CrowdStrike guidance. Align the lifecycle designation or separate the GA guidance so the page presents consistent maturity information, then review the rendered documentation for matching support messaging.

Written by the indexing model from the issue text.