feat: Add Amazon France search page with Crawl4AI anti-detection

- Created Amazon scraper service with advanced anti-bot techniques:
  * User-Agent rotation from realistic pool
  * Complete browser headers (Accept, Accept-Language, etc.)
  * Proxy rotation (10 residential proxies)
  * Random delays (1.5-4s) to mimic human behavior
  * Crawl4AI browser fingerprint randomization
  * NetworkIdle waiting for complete page load
  * Cookie acceptance automation

- Added Amazon search API endpoint with SSE streaming
  * Real-time progress updates
  * Proper error handling
  * Health check endpoint

- Created dedicated Amazon France frontend page:
  * Modern UI with product cards
  * Rating display (stars + review count)
  * Price formatting with discount badges
  * Prime badge support
  * Stock status indicators
  * Sponsored product labels
  * Direct Amazon links

- Removed store list (ENSEIGNES_DATA cleared)
  * Migration from discount stores to Amazon France
  * Catalog system kept for future use

- Updated navigation:
  * Added "Amazon France" menu item with ShoppingBag icon
  * Positioned between Search and Compare
  * Available on desktop and mobile

Technical stack:
- Backend: Crawl4AI + BeautifulSoup for scraping
- Frontend: React + Shadcn UI components
- API: FastAPI with SSE streaming

frontend/src/App.jsx

@@ -5,6 +5,7 @@ import Layout from '@/components/layout/Layout'
 import Dashboard from '@/pages/Dashboard'
 import Search from '@/pages/Search'
 import MultiSearch from '@/pages/MultiSearch'
+import AmazonSearch from '@/pages/AmazonSearch'
 import Catalogues from '@/pages/Catalogues'
 import Login from '@/pages/Login'
 import Admin from '@/pages/Admin'
@@ -78,6 +79,7 @@ function AppRoutes() {
                                     <Route path="/" element={<Dashboard />} />
                                     <Route path="/search" element={<Search />} />
                                     <Route path="/compare" element={<MultiSearch />} />
+                                    <Route path="/amazon" element={<AmazonSearch />} />
                                     <Route path="/catalogues" element={<Catalogues />} />
                                     <Route
                                         path="/admin"