docs(issue-5): phase 1 benchmark results, contract mapping, task checklist

Records the measured numbers and syncs every document that names the
delegation script paths, then bumps the framework to 4.3.0 in the three-way
lockstep (lib.sh, VERSIONS.md current + matrix, eight SKILL.md frontmatters).

phase1-benchmark.md carries both arms. The deterministic fake transport is what
CI asserts on: 50 publishes cost 50 connections one-shot and 1 persistent, p50
54.813ms -> 0.002ms. The real broker run is informational, since the PoC
default is a public broker: p50 1892.728ms -> 275.992ms, about 85% off.

It also corrects the plan's own estimate rather than repeating it. D8 predicted
the new shell path would drop from 3 forks to 2; the implementation is still 3,
because keeping the `_delegate_script publish_event.py` lookup is the only
thing that produces the "missing script tree does nothing" non-fatal contract
that C-02 pins. Saving that fork would change the contract, so it is deferred
to phase 4 rather than taken quietly.

SKILL.md gains the context table saying which tree wins where, so an operator
reading it knows a frozen loop runs frozen delegation code. The script paths in
every document remain correct and every quoted command still works verbatim.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UrDNJkHmm18uu7n7JwV5Qd

docs/contracts/issue-5/baseline.md

@@ -137,5 +137,5 @@ stateDiagram-v2
 | 오케스트레이터 CLI | `run_loop.sh` | `tests/test_loop_cli.py` | 9개 테스트 통과 |
 | 루프 가드 락 | `loop_lock.sh` | `tests/test_o2_race_free_lock.py` | 22개 테스트 통과 |
 | 반론 상한선 | `run_loop.sh` | `tests/test_o1_rebuttal.py` | 10개 테스트 통과 |
-| 위임 헬퍼 | `lib.sh` | `tests/test_tier1_unit.py` | 단위 테스트 통과 |
+| 위임 헬퍼 | `lib.sh` + `lib_py/delegation/` | `tests/test_issue5_phase1_delegation.py` | Phase 1 추출 완료 (v4.3.0); shim 경로·CLI 계약 불변 |
 | 작업 레지스트리 | `registry.py`, `mqtt_common.py` | `tests/test_tier2_component.py` | fcntl 기반 락킹 |