style: align comments with the project conventions

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.

hosts/neogaia/hardware-configuration.nix

@@ -1,6 +1,6 @@
 { lib, modulesPath, ... }:
 # Hardware detected by nixos-generate-config on this machine.
-# disko derives `fileSystems` and the LUKS device; none declared here.
+# disko derives `fileSystems` and the LUKS device, none declared here.
 {
   imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];