Git doesn't track empty directories, so config/claude/skills was missing
from the Nix store source path, breaking home.file.".claude/skills"
evaluation. Add a .gitkeep to keep the directory present until real
skills are added.
Add a home-manager module that symlinks config/claude/commands and
config/claude/skills into ~/.claude, mirroring the opencode module.
Seed the commands directory with a /commit slash command.
Add a "Code review pattern" section that tells the opencode agent to give
claude read-only access to the repo (Read/Grep/Glob plus a narrow git
allowlist) instead of gathering a full `git diff` and piping it in. The
piped-diff form loses surrounding-file context, bloats the prompt, and
falls over on large branches. Also adds a matching entry to "Don'ts" and
caveats the existing pipe-stdin example.
Motivated by an opencode run that collected the entire branch diff as
stdin instead of pointing claude at the working tree.
Adds metacfg.cli-apps.opencode (default enabled) which mounts the
in-repo opencode config (provider list, web-search skill) via
xdg.configFile, so all hosts pick it up automatically.
