Fix share button: add clipboard fallback for HTTP/mobile

frontend/src/components/RecommendationCard.tsx

@@ -27,11 +27,22 @@ export default function RecommendationCard({ recommendation, onToggleSave, onDis
     setSharing(true)
     try {
       const { share_url } = await shareRecommendation(recommendation.id)
-      await navigator.clipboard.writeText(share_url)
+      // Try clipboard first, fall back to prompt
+      try {
+        await navigator.clipboard.writeText(share_url)
+      } catch {
+        // Clipboard blocked (HTTP/mobile) — use fallback
+        const input = document.createElement('textarea')
+        input.value = share_url
+        document.body.appendChild(input)
+        input.select()
+        document.execCommand('copy')
+        document.body.removeChild(input)
+      }
       setShared(true)
       setTimeout(() => setShared(false), 2000)
     } catch {
-      // Fallback: if clipboard fails, silently ignore
+      // API call failed
     } finally {
       setSharing(false)
     }