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

app/routers/amazon.py

@@ -0,0 +1,120 @@
+"""
+API Router pour la recherche Amazon France
+Utilise Server-Sent Events (SSE) pour le streaming des résultats
+"""
+
+import json
+import logging
+from typing import AsyncGenerator
+
+from fastapi import APIRouter, Query
+from fastapi.responses import StreamingResponse
+from pydantic import BaseModel
+
+from app.services.amazon_scraper import scrape_amazon_search, AmazonProduct
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/api/amazon", tags=["amazon"])
+
+
+class AmazonSearchProgress(BaseModel):
+    """Progress model for SSE streaming"""
+    status: str  # 'searching', 'completed', 'error'
+    total: int
+    completed: int
+    message: str
+    results: list[dict]
+
+
+@router.get("/search")
+async def search_amazon(
+    q: str = Query(..., min_length=1, description="Terme de recherche"),
+    max_results: int = Query(20, ge=1, le=50, description="Nombre max de résultats"),
+):
+    """
+    Recherche de produits sur Amazon France.
+
+    Retourne un flux SSE avec les résultats.
+
+    Format des événements SSE:
+    - event: progress
+    - data: {"status": "...", "total": 1, "completed": 0/1, "results": [...]}
+    """
+
+    async def generate() -> AsyncGenerator[str, None]:
+        try:
+            # Initial progress
+            progress = AmazonSearchProgress(
+                status="searching",
+                total=1,
+                completed=0,
+                message=f"Recherche sur Amazon France: '{q}'...",
+                results=[]
+            )
+            yield f"event: progress\ndata: {progress.model_dump_json()}\n\n"
+
+            # Execute search
+            logger.info(f"Starting Amazon search for: {q}")
+            products = await scrape_amazon_search(q, max_results=max_results)
+
+            # Convert to dict
+            results = [p.model_dump() for p in products]
+
+            # Final progress
+            if results:
+                progress = AmazonSearchProgress(
+                    status="completed",
+                    total=1,
+                    completed=1,
+                    message=f"✅ {len(results)} produits trouvés",
+                    results=results
+                )
+            else:
+                progress = AmazonSearchProgress(
+                    status="completed",
+                    total=1,
+                    completed=1,
+                    message="Aucun produit trouvé",
+                    results=[]
+                )
+
+            yield f"event: progress\ndata: {progress.model_dump_json()}\n\n"
+
+        except Exception as e:
+            logger.error(f"Error during Amazon search: {e}", exc_info=True)
+            error_progress = AmazonSearchProgress(
+                status="error",
+                total=1,
+                completed=1,
+                message=f"Erreur: {str(e)}",
+                results=[]
+            )
+            yield f"event: progress\ndata: {error_progress.model_dump_json()}\n\n"
+
+    return StreamingResponse(
+        generate(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache",
+            "Connection": "keep-alive",
+            "X-Accel-Buffering": "no",
+        },
+    )
+
+
+@router.get("/health")
+async def amazon_health():
+    """Vérifie que le service Amazon est opérationnel"""
+    return {
+        "status": "ok",
+        "service": "Amazon France Scraper",
+        "anti_detection": "enabled",
+        "features": [
+            "User-Agent rotation",
+            "Proxy rotation (10 proxies)",
+            "Random delays",
+            "Realistic headers",
+            "Crawl4AI anti-detection"
+        ]
+    }