Apply a codebase-wide comment audit against the comment conventions:
split banned semicolons and multi-sentence lines into one sentence per
line, cut cross-file and history narration, trim file-top headers to a
single purpose line, and drop verbosity that did not earn its place.
Prose docs (CLAUDE.md, install.md) get the same one-sentence-per-line
and no-semicolon treatment.
Add a modules.desktop.userdirs module that declares the XDG user directories,
and route the recorder and screenshot tools through xdg-user-dir so their
output folders (Videos/Recordings, Pictures/Screenshots) follow one relocatable
source instead of a hardcoded $HOME path.
