v1.8.6 - No more false memory alerts inside Proxmox LXC

Fixes false memory-pressure alerts for DockTail running in Docker inside a Proxmox LXC container. Since 1.8.5 the agent reports the CT's memory from the containers' working sets, but active file cache still counted as used. A host that reads a lot of files (media servers, backups, nightly scans) could show 96% used while the CT had over 10 GB available. DockTail now leaves page cache out of the LXC figure, matching what free calls used. Bare-metal, VM and regular Docker hosts are unchanged. No Compose changes are required.

Open memory-pressure incidents caused by this clear on their own once the updated agent reports.

What's Changed

• Fix LXC host memory pressure accounting to exclude file cache by @marvinvr in #109

Full Changelog: 1.8.5...1.8.6