DOCUMENTATION.md said recent files were in-memory only and lost on vault
close, while the code persists them under waypointData.recentFiles; the
WaypointData/RecentFilesSettings/WaypointSettings snippets were also missing
real fields. Fix those, describe the new behaviour (single-writer saves,
settings-driven period detection, O(1) basename lookups, folder-aware rename
remapping, unified openPeriodNote, typechecked build), and trim Known
Limitations to the two still true (full-DOM redraw, CDN icon dependency).
QA.md: restate the 'No icon' case and add coverage for week-number
middle-click and for moving a folder that contains bookmarked files.
olivier