Results 2 issues of Lucas

Implement `java.io.Serializable` in kotlin data classes for `kotlin-spring` generator when `serializableModel` option is enabled. Fixes #8317. These existing samples clearly show the effect of this change, as they have `serializableModel`...

The state vectors produced by `doc.transact().state_vector().encode_v1()` and `encode_state_vector_from_update_v1()` are inconsistent with the attached document. [document.zip](https://github.com/user-attachments/files/20783648/document.zip) (The document is in the zip, github blocks most extensions). Below is a unit test...