Replace the `@{prompt}` placeholder with `{prompt}` across all skill docs and
agent-cli configs, remove the deprecated `--agent` flag from the invocation
syntax, delete the now-obsolete agent-cli test file, clarify that only one
triage label should be active at a time, and defer prompt-file cleanup to the
OS/child instead of removing it immediately after tmux launch.
- Replace `in-review` with `needs-review` in implement-issue workflow
- Document `needs-review` and `in-progress` labels in triage labels table
- Sync label definitions across setup-skills and docs/agents