Update changelogs from fern repo (#4452)

Co-authored-by: kennyderek <23439060+kennyderek@users.noreply.github.com>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2026-03-20.mdx

@@ -1,3 +1,11 @@
+## 4.38.0
+**`(feat):`** Auto-detect CI environment (GitHub Actions, GitLab CI, Bitbucket Pipelines)
+during `fern generate --docs` and send source metadata (repository, run ID,
+commit SHA, branch, actor) to FDR via the `X-CI-Source` header. This enables
+the deployment log UI to link docs deployments back to the CI workflow that
+triggered them.
+
+
 ## 4.37.12
 **`(fix):`** Scope allOf property merge to inline elements only in ObjectSchemaConverter and use first-match-wins for parent property resolution in V3 importer to match legacy behavior