Fix right-click download landing in home folder with wrong filename

Route context-menu captures through chrome.downloads so they resolve
Chrome's real filename (Content-Disposition, extension, etc.) via the
same onDeterminingFilename path auto-capture already uses, and harden
the native host against the bare-directory destDir KGet was misparsing
as a filename.

native-host/kget_capture_host.py

@@ -49,7 +49,12 @@ def add_transfer(url, filename):
     # sidesteps KGet's own filename guess, which is derived purely from the
     # URL path and gets it wrong for opaque/signed URLs.
     dest_dir = default_download_dir()
-    dest = os.path.join(dest_dir, filename) if filename else dest_dir
+    # A bare directory path with no trailing slash (e.g. "/home/ian/Downloads")
+    # gets misparsed by KGet's addTransfer as dir="/home/ian" + filename=
+    # "Downloads" -- the same split it applies to a real dir/filename path --
+    # landing the transfer in the parent directory instead. A trailing slash
+    # keeps it unambiguous when we don't have a real filename to append.
+    dest = os.path.join(dest_dir, filename) if filename else dest_dir.rstrip("/") + "/"
     cmd = [
         "dbus-send",
         "--print-reply",