tokrepo_codex_install
STEP 3 of ATOMIC ACTION 2 (install safely into this repo). Safely install a TokRepo asset into local Codex. Defaults to dry_run=true. To write files, set dry_run=false and confirm=true. Risky assets require stage=true or approve_risk=true. Always call tokrepo_install_plan + tokrepo_verify first. On any failure call tokrepo_rollback (STEP 4 — the escape).