fix(loop): resolve P0-1 (B-7) git diff CWD isolation and untracked file capture (20/20 PASS)

deploy/gitea-ci.yml

@@ -33,6 +33,7 @@ jobs:
           shellcheck .agents/skills/multi-agent-mux-stop/scripts/stop_session.sh
           shellcheck .agents/skills/multi-agent-mux-monitor/scripts/reconcile.sh
           shellcheck .agents/skills/multi-agent-mux-loop/scripts/run_loop.sh
+          shellcheck .agents/skills/multi-agent-mux-loop/scripts/diff_collect.sh
           shellcheck .agents/hooks/loop_delegation_guard.sh
           shellcheck deploy/lib_ownership.sh
           shellcheck deploy/install.sh