* feat(stack-management): add scan stacks folder button to detect manually-placed compose files
Users who place Docker Compose files directly into the stacks directory
(via SCP, file manager, etc.) can now click the folder-search icon next
to "Create Stack" to immediately discover and surface those stacks in
the sidebar without a full page reload.
* docs(troubleshooting): add scan stacks folder troubleshooting section
Covers common issues: compose file not in subdirectory, unrecognized
filenames, empty directories, and already-tracked stacks.