feat: Add smart package recommendations feature

- Implement onboarding modal with 3-step wizard
  - Category selection (up to 3 categories)
  - OS detection with manual override
  - Experience level selection

- Add intelligent recommendation engine
  - Hybrid scoring algorithm (category 40%, popularity 30%, OS 20%, preset 10%)
  - 7 curated categories with preset packages
  - Support for all platforms (Windows, macOS, Ubuntu, Debian, Arch, Fedora)

- Create recommendation UI components
  - RecommendationsSection with grid layout
  - Package cards with recommendation scores and reasons
  - User profile display with customization options

- Add localStorage-based profile management
  - Persistent user preferences
  - Automatic OS detection
  - Profile CRUD operations via useRecommendationProfile hook

- Implement API endpoint
  - POST /api/recommendations
  - GET /api/recommendations (query params)
  - Request validation and error handling

- Add full i18n support
  - English and Turkish translations
  - Onboarding flow, categories, and UI labels

- Update TypeScript config (lib: es2017 for array.includes)

Closes #1

src/types/recommendations.ts

@@ -0,0 +1,99 @@
+import { Package, Platform } from './index'
+
+/**
+ * User category types for package recommendations
+ */
+export type UserCategory = 
+  | 'development'
+  | 'design'
+  | 'multimedia'
+  | 'system-tools'
+  | 'gaming'
+  | 'productivity'
+  | 'education'
+
+/**
+ * User experience level
+ */
+export type ExperienceLevel = 'beginner' | 'intermediate' | 'advanced'
+
+/**
+ * User profile stored in localStorage
+ */
+export interface UserProfile {
+  categories: UserCategory[]
+  detectedOS?: string
+  selectedOS?: string // Manual override
+  experienceLevel?: ExperienceLevel
+  hasCompletedOnboarding: boolean
+  createdAt: string
+  lastUpdated: string
+}
+
+/**
+ * Request payload for recommendation API
+ */
+export interface RecommendationRequest {
+  platform_id: string
+  categories: UserCategory[]
+  experienceLevel?: ExperienceLevel
+  limit?: number
+}
+
+/**
+ * Recommended package with score
+ */
+export interface RecommendedPackage {
+  id: string
+  name: string
+  description: string
+  version: string
+  category?: string
+  license?: string
+  type: 'gui' | 'cli'
+  platform?: string | any
+  platform_id?: string
+  repository: 'official' | 'third-party' | 'aur'
+  download_url?: string
+  lastUpdated?: string
+  downloads?: number
+  popularity?: number
+  popularity_score?: number
+  tags?: string[]
+  recommendationScore: number
+  recommendationReason: string
+  presetMatch?: boolean
+}
+
+/**
+ * Preset package configuration
+ */
+export interface PackagePreset {
+  packageName: string
+  platforms: string[] // ['windows', 'macos', 'ubuntu', 'arch', 'fedora']
+  priority: number // 1-10, higher = more important
+  reason: string // Why this package is recommended
+  experienceLevel?: ExperienceLevel[] // Target experience levels
+}
+
+/**
+ * Category preset configuration
+ */
+export interface CategoryPreset {
+  category: UserCategory
+  packages: PackagePreset[]
+  description: string
+  icon: string
+}
+
+/**
+ * Recommendation response
+ */
+export interface RecommendationResponse {
+  recommendations: RecommendedPackage[]
+  total: number
+  userProfile: {
+    categories: UserCategory[]
+    platform: string
+  }
+}