fix: paid video preview plays in lightbox, better error messages

Video thumbnail in card is pointer-events-none so clicks pass through
to the play handler. Better error messages when preview fetch fails.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/views/PeerFiles.vue

@@ -89,7 +89,7 @@
           <video
             v-else-if="item.mime_type.startsWith('video/') && previewUrls[item.id]"
             :src="previewUrls[item.id]"
-            class="w-full h-full object-cover"
+            class="w-full h-full object-cover pointer-events-none"
             muted
             autoplay
             loop
@@ -535,9 +535,11 @@ async function playMedia(item: CatalogItem) {
         videoPlayerUrl.value = blobUrl
         videoPlayerPaid.value = paid
       }
+    } else {
+      purchaseError.value = 'No preview data returned — peer may be offline'
     }
-  } catch {
-    purchaseError.value = 'Failed to load media for playback'
+  } catch (e: unknown) {
+    purchaseError.value = e instanceof Error ? e.message : 'Failed to load media — peer may be offline'
   } finally {
     playing.value = null
   }