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.

modules/agents/tools/gitea-axi.nix

@@ -5,8 +5,6 @@
   ...
 }:
 # gitea-axi for the primary user, installed through its own home-manager module.
-# That module also declares the Claude Code context when that harness is
-# enabled on the host; enabling this alone installs the CLI and nothing else.
 let
   cfg = config.modules.agents.tools.gitea-axi;
   user = config.user.name;