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.
Route the volume and brightness keys through swayosd-client, which raises
a transient on-screen popup that auto-hides a moment after the last press,
so the level is visible while adjusting without a permanent widget. A new
osd module runs the server for the graphical session and makes the
backlight node group-writable so it dims without root.
Supersedes the plain brightnessctl binds, whose control swayosd bundles.
