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/auth.ts

@@ -4,7 +4,7 @@ import Credentials from '@auth/core/providers/credentials';
 import Google from '@auth/core/providers/google';
 import type { OAuthConfig } from '@auth/core/providers';
 import { db } from '$lib/server/db';
-import { users } from '$lib/server/schema';
+import { users } from '$lib/db/schema';
 import { eq } from 'drizzle-orm';
 import bcrypt from 'bcrypt';
 import { env } from '$env/dynamic/private';