fix: pre-hydration navbar color to prevent flash, fix hydration mismatch in color picker

src/app/layout.tsx

@@ -42,7 +42,7 @@ export default async function RootLayout({ children }: { children: ReactNode })
         {/* Apply the saved/default theme before first paint to avoid a flash. */}
         <script
           dangerouslySetInnerHTML={{
-            __html: `try{var s=localStorage.getItem('theme');if(s==='dark'||(!s&&${defaultDark}))document.documentElement.classList.add('dark');}catch(e){}`,
+            __html: `try{var s=localStorage.getItem('theme');if(s==='dark'||(!s&&${defaultDark}))document.documentElement.classList.add('dark');var nc=localStorage.getItem('navbarColor'),nt=localStorage.getItem('navbarTextColor');if(nc)document.documentElement.style.setProperty('--color-navbar',nc);if(nt)document.documentElement.style.setProperty('--color-navbar-text',nt);}catch(e){}`,
           }}
         />
       </head>