Persist theme selection in localStorage

[BharathASL]

Problem

The light/dark theme toggle (toggleThemeType() in index.html) is reset on every page reload. Users have to re-toggle on every visit.

Fix

Update toggleThemeType() and add an init block:

function toggleThemeType() {
    const isLight = $('html').hasClass('light');
    $('html').toggleClass('light', !isLight).toggleClass('dark', isLight);
    localStorage.setItem('theme', isLight ? 'dark' : 'light');
}

// On page load, apply saved theme
const savedTheme = localStorage.getItem('theme') || 'dark';
$('html').removeClass('light dark').addClass(savedTheme);