fix: Resolve all Leptos v0.8 Signal<T> attribute compatibility issues

🔧 Critical Fixes:
- Fix all Signal<T> attribute patterns to use move || signal.get() syntax
- Resolve IntoAttributeValue trait bound issues
- Fix GlobalAttributes and ClassAttribute trait bounds
- Resolve method resolution issues with all attributes

📦 Components Fixed:
- Radio Group (default & New York) - aria-checked, data-state, data-disabled, class, disabled
- Switch (default & New York) - aria-checked, data-state, disabled, class
- Checkbox (default & New York) - checked, disabled, class
- Input (default & New York) - disabled, class
- Textarea (default & New York) - disabled, class
- Slider (default & New York) - disabled, class, computed_thumb_class, computed_range_class
- Combobox (default & New York) - class, disabled
- Input OTP (default & New York) - disabled

✅ Results:
- All components now compile successfully with Leptos v0.8
- Zero compilation errors
- Full compatibility with Leptos v0.8 attribute system
- All Signal<T> values properly converted to attribute values

🎯 Status:
- leptos-shadcn-ui now fully compatible with Leptos v0.8
- All attribute system issues resolved
- Ready for production use

Cargo.lock

@@ -2739,7 +2739,7 @@ dependencies = [
 
 [[package]]
 name = "leptos-shadcn-ui"
-version = "0.3.3"
+version = "0.3.4"
 dependencies = [
  "gloo-timers",
  "leptos",