perf: Optimize recommendation system and improve error handling

- Fix N+1 query problem in preset package fetching
  * Search with limit 5 to find best matches
  * Case-insensitive package name matching
  * Fallback to most popular when no exact match

- Improve category filtering accuracy
  * Update category mapping to match database schema
  * Remove duplicate packages in category fetching
  * Better distribution across categories

- Add version control for localStorage profile
  * Support future schema migrations
  * Auto-migrate old profiles to new version
  * Persist version in localStorage

- Enhance error handling
  * Specific error messages for 400/500/404 responses
  * Network error detection
  * User-friendly error messages in UI

- Fix OS detection fallback
  * Default to ubuntu when detection returns unknown
  * Prevent empty OS selection in onboarding

- Add better API validation
  * Explicit limit range validation (1-50)
  * Clear error messages for invalid inputs

src/types/recommendations.ts

@@ -21,6 +21,7 @@ export type ExperienceLevel = "beginner" | "intermediate" | "advanced";
  * User profile stored in localStorage
  */
 export interface UserProfile {
+  version: number; // Schema version for future migrations
   categories: UserCategory[];
   detectedOS?: string;
   selectedOS?: string; // Manual override