update: improve project structure and add linting/formatting

- Remove duplicate lucide-svelte package, keep @lucide/svelte
- Move schema from src/lib/server/ to src/lib/db/ for better organization
- Add path aliases to svelte.config.js (, , , , )
- Add ESLint and Prettier configuration with 2-space indentation
- Update all imports to use new schema location and icon package

src/lib/components/ui/theme-toggle/ThemeToggle.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { themeStore } from '$lib/stores/theme.svelte';
-	import { Sun, Moon, Monitor } from 'lucide-svelte';
+	import { Sun, Moon, Monitor } from '@lucide/svelte';
     import IconButton from '../IconButton.svelte';
 
 	let {