fix: implement persistent MongoDB connections and resolve race conditions

- Replace connect/disconnect pattern with persistent connection pool
- Add explicit database initialization on server startup
- Remove all dbDisconnect() calls from API endpoints to prevent race conditions
- Fix MongoNotConnectedError when scheduler runs concurrently with API requests
- Add connection pooling with proper MongoDB driver options
- Add safety check for recipes array in favorites utility

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/lib/server/favorites.ts

@@ -24,6 +24,12 @@ export async function getUserFavorites(fetch: any, locals: any): Promise<string[
 }
 
 export function addFavoriteStatusToRecipes(recipes: any[], userFavorites: string[]): any[] {
+    // Safety check: ensure recipes is an array
+    if (!Array.isArray(recipes)) {
+        console.error('addFavoriteStatusToRecipes: recipes is not an array:', recipes);
+        return [];
+    }
+    
     return recipes.map(recipe => ({
         ...recipe,
         isFavorite: userFavorites.some(favId => favId.toString() === recipe._id.toString())