🧹 chore: merge main

Author: SaltyAom

CHANGELOG.md

@@ -1,3 +1,11 @@
+# 1.4.19 - 9 Dec 2025
+Improvement
+- [#1588](https://github.com/elysiajs/elysia/pull/1588), [#1587](https://github.com/elysiajs/elysia/pull/1587) add seen weakset during mergeDeep
+- [#1607](https://github.com/elysiajs/elysia/issues/1607), [#1606](https://github.com/elysiajs/elysia/issues/1606), [#1139](https://github.com/elysiajs/elysia/issues/1138) nested form data
+
+Bug fix:
+- [#1591](https://github.com/elysiajs/elysia/pull/1591), [#1590](https://github.com/elysiajs/elysia/pull/1591) merge set.headers without duplicating Response
+
 # 1.4.18 - 4 Dec 2025
 Security:
 - use `JSON.stringify` over custom escape implementation