fix(issue-5): address phase 1 cross-review findings (R1, R2, F-1)

Three reviewers examined fc0bd96..8def235. Codex and Claude each reproduced a
defect; all three findings were re-verified here before being accepted, and none
were rebutted.

R1 (codex) — the shell helpers ran `python -m lib_py.delegation.cli`. For -m,
sys.path[0] is the working directory, which therefore beats PYTHONPATH: with cwd
inside a tree containing lib_py, the live package won even with the frozen path
listed first. The documented B-13 guarantee for this path did not hold.
Reproduced, then replaced with an explicit bootstrap that inserts SKILL_DIR
itself. cwd is left alone, because the registry and audit-log paths are relative
to it. The file-based shim path was never affected.

R2 (codex) — the persistent connection was reused on host and port alone. Two
jobs sharing an endpoint but carrying different credentials or TLS settings
silently published over the first connection. Reproduced (the client factory ran
once, under the first account, with TLS off). The guard now compares an
immutable snapshot of the whole connection identity and names only the differing
field, never its value.

F-1 (claude) — paho queues a publish issued while disconnected and raises
RuntimeError from wait_for_publish. RuntimeError is deliberately outside the
retry tuple, so the one state a persistent connection exists to survive, the gap
between a drop and paho's reconnect, failed on the first attempt. Confirmed
against paho 2.1.0. That single condition is now translated into a retryable
error; the tuple is unchanged, so genuine programming errors are still not
retried.

Two fixtures were hiding these: FakeInfo had no rc and never raised. It now
mirrors paho's contract, which is what makes the new tests meaningful.

Also folds in the duplication both Claude (O-1) and I had flagged: the CLI path
kept its own copy of connect-publish-disconnect plus its own timeout constants.
_publish_once now delegates to OneShotPublisher.publish_raw, so a transport fix
lands once. Having two copies is exactly why these bugs existed in one of them.

Documentation corrected rather than defended: the benchmark's rationale for
keeping three forks was imprecise (the || true already guarantees rc 0; the
lookup buys quietness and legacy parity), SKILL.md no longer claims PYTHONPATH
decides the frozen path, and the daemon's directory creation is recorded as a
deliberate difference. Trailing whitespace inherited by the relocated file is
stripped, so the commit range is now clean too.

Verified: each regression fails against the pre-fix code and passes after
(R1 1, R2 4, F-1 1). 66 phase-1 tests pass.

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

docs/contracts/issue-5/phase1-benchmark.md

@@ -68,7 +68,9 @@ Rev.1 계획 job의 `started` 이벤트는 payload timestamp 05:58:49Z에서 모
 | 레거시 (`_delegate_publish_event_legacy`) | 3 (`$(_delegate_py_bin)`, `$(_delegate_script)`, python) |
 | 신규 (`-m lib_py.delegation.cli`) | 3 (`$(_delegate_py_bin)`, `$(_delegate_script)`, python) |
 
-> 계획서 D8은 신규 경로가 2 fork일 것으로 예상했으나, **실제 구현은 3 fork로 동일하다.** `_delegate_script publish_event.py` 호출을 유지했기 때문이며, 이는 의도적이다: 그 호출이 "스크립트 트리가 없으면 아무 것도 하지 않는다"는 비치명 계약(C-02)을 만들어내는 유일한 지점이다. 이를 제거하면 fork 1회를 아끼는 대신 계약이 바뀐다. fork 절감은 Phase 4에서 계약과 함께 재검토한다.
+> 계획서 D8은 신규 경로가 2 fork일 것으로 예상했으나, **실제 구현은 3 fork로 동일하다.** `_delegate_script publish_event.py` 조회를 유지했기 때문이다.
+>
+> **이 조회가 실제로 보장하는 것 (교차 리뷰 `cc3468cb` 정정)**: 초기 서술은 이 조회가 "비치명 계약(C-02)을 만드는 유일한 지점"이라고 했으나 부정확하다. rc 0 자체는 `delegate_publish_event`의 `|| true`만으로도 보장되고, C-02도 rc만 단정한다. 조회가 보장하는 것은 **위임 스크립트 트리가 없을 때 인터프리터를 아예 띄우지 않아 stderr에 트레이스백을 남기지 않는다는 정숙성과, 레거시 본체와의 동작 동일성**이다(인터프리터 미호출 단정은 C-01에 있다). 유지 결정 자체는 세 리뷰어 전원이 지지했으며, fork 절감은 Phase 4에서 이 계약과 함께 재검토한다.
 
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