fix: handle boolean true in nativeStyleMapping

[danstepanov]

Summary

• nativeStyleMapping allows true as a value (e.g. textAlign: true on TextInput, backgroundColor: true on ImageBackground), meaning "extract this property from style and set it as a prop with the same name"
• The runtime called path.split(".") which throws TypeError on boolean true
• Fixed by converting true to the key name during config creation in useNativeCss, so the runtime always receives strings

Test plan

• Added 3 tests: boolean mapping extracts prop, works alongside other styles, works on custom styled() components
• Full suite passes (1043 passed, 0 failures)

Fixes #232
Supersedes #251

[YevheniiKotyrlo]

Thanks for picking this up! One small thing that might be worth an extra test: src/components/ImageBackground.tsx also uses the true form (backgroundColor: true), so the same crash reproduces on <ImageBackground className="bg-*">, not just TextInput. Issue #232 only mentioned TextInput, and the tests here cover TextInput + a custom styled() — adding an ImageBackground case would lock in the second shipped wrapper that hits this path.