add-rtk

# Add rtk Install [rtk](https://github.com/rtk-ai/rtk) — a CLI proxy delivering 60–90% token savings on common dev commands (git, cargo, pytest, docker, kubectl, etc.) — and wire it transparently into agent containers via the Claude Code `PreToolUse` hook. ## What this sets up - `rtk` binary at `~/.local/bin/rtk` on the host - `~/.local/bin/rtk` mounted read-only at `/usr/local/bin/rtk` inside the target agent group's containers - `PreToolUse` hook in the agent group's `settings.json` so every Bash call is automatically filtered through rtk — no CLAUDE.md instructions needed ## Integration tests This skill has **no in-tree integration test** by design. Its only functional reach-ins are runtime operator actions — the host-only `ncl groups config add-mount` (Step 3) and the `settings.json` `PreToolUse` hook write (Step 4) — neither of which leaves a line in the source tree whose deletion a test could catch. There are no package dependencies or Dockerfile edits to guard either. Conformance is idempotent apply + `REMOVE.md`; the mount and hook are verified at runtime (see Verify). ## Step 1 — Install rtk on the host ```bash curl -fsSL https://raw.githubusercontent.com/rtk-ai/rtk/refs/heads/master/install.sh | sh ``` If the script put the binary elsewhere, move it: ```bash find ~/.local ~/.cargo/bin ~/bin -name rtk 2>/dev/null mv "$(which rtk 2>/dev/null)" ~/.local/bin/rtk ``` Verify: ```bash ~/.local/bin/rtk --version chmod +x ~/.local/bin/rtk # if needed ``` ## Ste...