Move SFX settings controls to Kotlin

[xarmaq]

What changed

• moved the SFX expandable header and child checkbox creation out of settings.py
• added the Kotlin-backed SfxNative builders for expandable items and the volume slider
• connected the new builders through sfx.py and dexLoader.py
• shipped the generated sfx.dex
• kept a Python fallback for hosts where the native controls cannot be loaded

Why

The SFX page previously owned its controls indirectly through the large shared settings module. Moving the controls to the Kotlin dex reduces Python-to-Java UI construction and keeps SFX-specific code inside the SFX module.

Validation

• compiled all Python sources
• compiled the Kotlin sources with Kotlin 2.0.21
• generated and inspected sfx.dex with R8/D8
• built PackIt-0.0.0-rc.652-3.11.eaf with elyb build -c 2 -nf -v