feat(cli): replace the classic coreutils tools with modern equivalents

Adds Rust/Go replacements for the day-to-day utilities and shadows four of
them with aliases. Only read-only commands are shadowed (cat, du, df, ps), so a
wrong flag costs a retype rather than data; rm, grep, find and sed keep their
originals and the replacements are reached by their own names.

The aliases land in .zshrc, so they apply to interactive zsh only -- scripts,
`sudo <cmd>` and anything exec'd by another program still get the real binary.

New on every host: dust, dysk, procs, trash-cli, doggo, xh, ouch, jnv, hexyl,
fq and tealdeer. dysk is used rather than duf, which is unmaintained upstream.

git gains difftastic behind a `git dft` alias. diff.external is deliberately
left unset so delta remains the renderer for git diff/show and for anything
parsing them.

The work box gains kubecolor, aliased over kubectl; it wraps the real kubectl
and drops colour when stdout is not a terminal, so pipes are unchanged.

home/README.md documents the alias map, the flag incompatibilities (including
the two that fail silently: dust -s is --apparent-size, and procs reads a bare
`aux` as a search keyword) and the rationale for what was left alone.

README.md

@@ -180,6 +180,9 @@ automatically.
 
 - Interactive shell features (zsh, tmux, git, ssh, CLI tools, auto-tmux):
   [`home/README.md`](./home/README.md).
+- Which classic utilities are shadowed by modern replacements, and the flag
+  differences that will bite:
+  [`home/README.md` → "Replacing the classics"](./home/README.md#replacing-the-classics).
 - All Sway / tmux / foot / zsh keyboard shortcuts:
   [`home/KEYBINDINGS.md`](./home/KEYBINDINGS.md).