fix: kotlin serialization version and jvm bindings

[ovitrif]

Summary

Upgrade Kotlin and related dependencies to 2.x for compatibility with consuming apps. Add serialization support to JVM bindings for parity with Android.

Changes

Dependency	Before	After
Kotlin	1.9.20	2.2.0
kotlinx-serialization-json	1.6.0	1.9.0
kotlinx-coroutines-core	1.6.4	1.10.2
atomicfu	0.23.1	0.27.0
Gradle (JVM)	7.6	8.0

JVM Bindings

• Added uniffi-jvm.toml with generate_serializable_types = true
• Updated bindgen script to use gobley-uniffi-bindgen
• Added serialization dependencies to build.gradle.kts
• Fixed version property on lib submodule for JitPack POM generation

Release

• v0.7.0-rc.17

[ovitrif]

@ben-kaufman Tested serialization and jvm in bitkit-android, can be merged

[ben-kaufman]

Should version be rc.16 or rc.17? I see last release says rc.17

[ovitrif]

Should version be rc.16 or rc.17? I see last release says rc.17

17, this was on top of the old one. Tested in android using 17 👍🏻