[Bridge] Improve working directory handling
[Bridge] Improve working directory handling

- Initialize with null to prevent leaking configurations
- Check if the working directory is a directory
- Store the real path instead of raw data
- Add final path separator as expected by Bridge::create

kranack/rss-bridge,sebsauvage/rss-bridge,RSS-Bridge/rss-bridge,simonbru/rss-bridge,ORelio/rss-bridge,simonbru/rss-bridge,kranack/rss-bridge,ORelio/rss-bridge,ORelio/rss-bridge,Riduidel/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,RSS-Bridge/rss-bridge,Frenzie/rss-bridge,Frenzie/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,RSS-Bridge/rss-bridge