Update changelogs from fern repo (#4263)

Co-authored-by: patrickthornton <70873350+patrickthornton@users.noreply.github.com>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2026-03-13.mdx

@@ -1,3 +1,23 @@
+## 4.28.0
+**`(feat):`** Add `coerce-consts-to` setting for controlling how OpenAPI/AsyncAPI
+`const` values are represented. Set to `literals` to convert them directly
+to literals with defaults; set to `enums` (the default, current behavior)
+to convert them to single-valued and therefore extensible enums.
+
+When `coerce-consts-to` is `enums`, the `coerce-enums-to-literals` setting
+will not transitively apply to const-originated enums, keeping the two
+concepts independent.
+
+Usage:
+```yaml
+api:
+  specs:
+    - asyncapi: ./asyncapi.yaml
+      settings:
+        coerce-consts-to: literals
+```
+
+
 ## 4.27.0
 **`(feat):`** Log detected .fernignore paths when copying generated files. When a
 .fernignore file is present in the output directory, the CLI now emits