debug: log product search result to trace not_found issues

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/products/search/route.ts

@@ -10,9 +10,11 @@ export async function GET(req: NextRequest) {
 
   try {
     const result = await searchProductByRef(ref.trim())
+    console.log(`[search] ref="${ref.trim()}" → found=${result.found} id=${(result as {shopifyId?: string}).shopifyId ?? '-'}`)
     return NextResponse.json(result)
   } catch (err) {
     const message = err instanceof Error ? err.message : 'Erreur inconnue'
+    console.error(`[search] ref="${ref.trim()}" → ERROR: ${message}`)
     return NextResponse.json({ error: message }, { status: 500 })
   }
 }