refactor(theme): update neutral color from gray to slate

src/styles/theme.ts

@@ -9,9 +9,9 @@ export const breakpoints = {
 } satisfies ThemeConfig['breakpoints']
 
 export const themeConfig: ThemeConfig = {
-  neutral: 'gray',
+  neutral: 'slate',
   colorVariation: { dark: true, alpha: false, p3: false },
-  includeColors: ['teal', 'gray'],
+  includeColors: ['teal', 'slate'],
   semanticColors: { primary: 'teal' },
   breakpoints
 }