fix: burn file items after download, not metadata fetch

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/items.py

@@ -134,20 +134,27 @@ def get_file_item(db: Session, slug: str) -> Item | None:
     return item
 
 
+def burn_file_item(db: Session, item: Item) -> None:
+    """Mark a file item burned and remove its bytes from disk."""
+    item.burned = True
+    path = resolve_file_path(item)
+    db.commit()
+    if path is not None:
+        try:
+            path.unlink(missing_ok=True)
+        except OSError:
+            pass
+
+
 def get_item(db: Session, slug: str) -> Item | None:
     item = db.scalar(select(Item).where(Item.slug == slug))
     if item is None or _is_unavailable(item):
         return None
 
     item.view_count += 1
-    if item.burn_after_read:
+    # File items burn on download, not metadata fetch.
+    if item.burn_after_read and item.kind != "file":
         item.burned = True
-        path = resolve_file_path(item)
-        if path is not None:
-            try:
-                path.unlink(missing_ok=True)
-            except OSError:
-                pass
     db.commit()
     db.refresh(item)
     return item