feat: implement dark mode with theme toggle

- Add dark mode support across all components and pages
- Implement theme toggle button in navbar (desktop and mobile)
- Fix desktop theme toggle icon visibility issue
- Add dark mode color variants to all text, backgrounds and components
- Update Tailwind config to enable class-based dark mode
- Add dark mode support to prose styles for blog content
- Persist theme preference in localStorage
- Update all pages (index, bio, blog) with dark mode colors
- Optimize images (me.png and me-baby.jpg)

tailwind.config.js

@@ -1,6 +1,7 @@
 /** @type {import('tailwindcss').Config} */
 export default {
 	content: ["./src/**/*.{astro,html,js,jsx,md,mdx,svelte,ts,tsx,vue}"],
+	darkMode: 'class',
 	theme: {
 		colors: {
 			white: "#ffffff",