Update changelogs from fern repo (#5247)

Co-authored-by: dsinghvi <10870189+dsinghvi@users.noreply.github.com>

Author: fern-support

fern/products/sdks/generators/typescript/changelog/2026-04-29.mdx

@@ -1,3 +1,9 @@
+## 3.66.6
+**`(fix):`** Fix TS2322 type error in generated serialization files when `enableForwardCompatibleEnums` is enabled.
+The enum schema builder now uses `forwardCompatibleEnum_` which correctly widens the parsed type to `string`,
+matching the widened API type.
+
+
 ## 3.66.5
 **`(fix):`** Fix generated wire tests for SSE endpoints with protocol-discriminated unions.
 The expected event assertion no longer wraps the deserialized data in a duplicate