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/language-toggle/LanguageToggle.svelte

@@ -2,7 +2,7 @@
 	import { languageStore } from '$lib/stores/language.svelte';
 	import { languages } from '$lib/i18n/translations';
 	import Dropdown from '$lib/components/ui/Dropdown.svelte';
-	import { Languages } from 'lucide-svelte';
+	import { Languages } from '@lucide/svelte';
 
 	let { color }: { color?: string | null } = $props();