refactor(ui): centralize prop resolution in useDefinition

Extract prop-splitting and responsive resolution with default
fallbacks from `useDefinition` into a new `resolveDefinitionProps`
helper. This makes `propDefs.default` the single authoritative
source of truth for default values.

Previously, `useBgProvider` had a separate manual default lookup
(`props.bg ?? (definition.propDefs as any).bg?.default`) that
duplicated the main resolution loop.

Signed-off-by: Johan Persson <johanopersson@gmail.com>

packages/ui/src/hooks/useDefinition/helpers.ts

@@ -16,7 +16,7 @@
 
 import { breakpoints } from '../useBreakpoint';
 import { utilityClassMap } from '../../utils/utilityClassMap';
-import type { UnwrapResponsive, UtilityStyle } from './types';
+import type { ComponentConfig, UnwrapResponsive, UtilityStyle } from './types';
 
 const namedBreakpoints = breakpoints.filter(b => b.id !== 'initial');
 
@@ -57,6 +57,42 @@ export function resolveResponsiveValue<T>(
   return value as UnwrapResponsive<T>;
 }
 
+export function resolveDefinitionProps<D extends ComponentConfig<any, any>>(
+  definition: D,
+  props: Record<string, any>,
+  breakpoint: string,
+): {
+  ownPropsResolved: Record<string, any>;
+  restProps: Record<string, any>;
+} {
+  const ownPropKeys = new Set(Object.keys(definition.propDefs));
+  const utilityPropKeys = new Set(definition.utilityProps ?? []);
+
+  const ownPropsRaw: Record<string, any> = {};
+  const restProps: Record<string, any> = {};
+
+  for (const [key, value] of Object.entries(props)) {
+    if (ownPropKeys.has(key)) {
+      ownPropsRaw[key] = value;
+    } else if (!(utilityPropKeys as Set<string>).has(key)) {
+      restProps[key] = value;
+    }
+  }
+
+  const ownPropsResolved: Record<string, any> = {};
+
+  for (const [key, config] of Object.entries(definition.propDefs)) {
+    const rawValue = ownPropsRaw[key];
+    const resolvedValue = resolveResponsiveValue(rawValue, breakpoint);
+    const finalValue = resolvedValue ?? (config as any).default;
+    if (finalValue !== undefined) {
+      ownPropsResolved[key] = finalValue;
+    }
+  }
+
+  return { ownPropsResolved, restProps };
+}
+
 export function processUtilityProps<Keys extends string>(
   props: Record<string, any>,
   utilityPropKeys: readonly Keys[],

packages/ui/src/hooks/useDefinition/useDefinition.tsx

@@ -18,7 +18,7 @@ import { ReactNode } from 'react';
 import clsx from 'clsx';
 import { useBreakpoint } from '../useBreakpoint';
 import { useBgProvider, useBgConsumer, BgProvider } from '../useBg';
-import { resolveResponsiveValue, processUtilityProps } from './helpers';
+import { resolveDefinitionProps, processUtilityProps } from './helpers';
 import type {
   ComponentConfig,
   UseDefinitionOptions,
@@ -36,41 +36,19 @@ export function useDefinition<
 ): UseDefinitionResult<D, P> {
   const { breakpoint } = useBreakpoint();
 
-  // Provider: resolve bg and provide context for children
-  const providerBg = useBgProvider(
-    definition.bg === 'provider'
-      ? props.bg ?? (definition.propDefs as any).bg?.default
-      : undefined,
+  // Resolve all props centrally — applies responsive values and defaults
+  const { ownPropsResolved, restProps } = resolveDefinitionProps(
+    definition,
+    props,
+    breakpoint,
   );
 
-  // Consumer: read parent context bg
-  const consumerBg = useBgConsumer();
-
-  const ownPropKeys = new Set(Object.keys(definition.propDefs));
-  const utilityPropKeys = new Set(definition.utilityProps ?? []);
-
-  const ownPropsRaw: Record<string, any> = {};
-  const restProps: Record<string, any> = {};
-
-  for (const [key, value] of Object.entries(props)) {
-    if (ownPropKeys.has(key)) {
-      ownPropsRaw[key] = value;
-    } else if (!(utilityPropKeys as Set<string>).has(key)) {
-      restProps[key] = value;
-    }
-  }
-
-  const ownPropsResolved: Record<string, any> = {};
   const dataAttributes: Record<string, string | undefined> = {};
 
   for (const [key, config] of Object.entries(definition.propDefs)) {
-    const rawValue = ownPropsRaw[key];
-    const resolvedValue = resolveResponsiveValue(rawValue, breakpoint);
-    const finalValue = resolvedValue ?? (config as any).default;
+    const finalValue = ownPropsResolved[key];
 
     if (finalValue !== undefined) {
-      ownPropsResolved[key] = finalValue;
-
       // Skip data-bg for bg prop when the provider path handles it
       if (key === 'bg' && definition.bg === 'provider') continue;
 
@@ -81,6 +59,14 @@ export function useDefinition<
     }
   }
 
+  // Provider: resolve bg and provide context for children
+  const providerBg = useBgProvider(
+    definition.bg === 'provider' ? ownPropsResolved.bg : undefined,
+  );
+
+  // Consumer: read parent context bg
+  const consumerBg = useBgConsumer();
+
   // Provider: set data-bg from the resolved provider bg
   if (definition.bg === 'provider' && providerBg.bg !== undefined) {
     dataAttributes['data-bg'] = String(providerBg.bg);