feat(IMP-17): AI repair fallback infra carve-out — design-only boundary + 3-cond AND gate

u1 — src/phase_z2_pipeline.py:564 route hint comment corrected from
non-existent IMP-31 to IMP-17 (carve-out, AI fallback only, normal path 밖).
Line 565 IMP-29 frontend override reference untouched.

u2 — docs/architecture/IMP-17-CARVE-OUT.md (new) defines:
- allowed scope (Step 12 restructure proposal, Step 16/17 retry fallback)
- forbidden scope (normal-path AI calls, MDX compression, HTML structure)
- 3-condition AND activation gate (User GO ∧ B4 frame_selection evidence
  ∧ IMP-04 catalog + IMP-05 V4 fallback live)
- pattern shape reference (link-only): content_editor.py:21,318 +
  sse_utils.py:16-50 (Phase Q Archive Candidate, no port)
- AI 격리 contract + Kei persona 단절 (permanent)

u3 — PHASE-Z-IMPLEMENTATION-ISSUE-BACKLOG.md:68 IMP-17 row gains
carve-out doc link + 3-cond AND gate pointer.

u4 — PHASE-Q-INSIGHT-TO-22STEP-MAP.md AI repair fallback infra registry
row prefixed with IMP-17 + carve-out link; normal_path=no preserved.

Anchor test: tests/orchestrator_unit/test_imp17_comment_anchor.py asserts
line 564 IMP-17 wording AND line 565 IMP-29 preservation (2 tests pass).

Runtime behavior change: 0. Only delta in executable file is one comment
line. Normal-path AI invocation count remains 0.

Refs: gitea #17

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/architecture/PHASE-Z-IMPLEMENTATION-ISSUE-BACKLOG.md

@@ -65,7 +65,7 @@
 | IMP-14 | A-4 slide-base iframe mode | Step 13 | §3 새로 만들기 | ↓ low | `slide-base.html` conditional CSS (embedded vs standalone) | Claude / Phase R' HTML generation 회귀 X / Jinja2 deterministic | none | pending |
 | IMP-15 | Step 14 visual_check 보강 | Step 14, 21 | §3 H1 Reference Only | medium | image_aspect_mismatch / tabular_overflow 검사 추가 | AI/Kei classification 회귀 X / deterministic 검사 + trace | soft link: IMP-01 (Step 14 측정/trace layer 공유) | pending |
 | IMP-16 | B-2 verification 보조 axis | Step 1, 2, 14, 21, 22 | §3 H3 Reference Only | ↓ low | B-2 reverse path 의 verification 보조. main reverse path 는 IMP-07, 본 issue 는 text/visual/trace 검증 layer | AI/Kei verification 회귀 X / utility deterministic | hard link: IMP-07 (B-2 main 활성 시점 의미) | pending |
-| **IMP-17** | **AI repair fallback infra** (**carve-out — normal path 밖**) | Step 12, 16, 17 | §3 G3 | (별 axis priority — pending) | `httpx` + SSE streaming + retry + JSON parse pattern reference — light_edit / restructure proposal | **normal path AI 호출 0 — 본 axis = fallback only, normal path 와 분리 설계** / Kei persona 단절 (Phase Q 자산과 단절) | soft link: IMP-04 + IMP-05 (catalog 확장 + V4 fallback 활성 시 의미) | pending |
+| **IMP-17** | **AI repair fallback infra** (**carve-out — normal path 밖**) | Step 12, 16, 17 | §3 G3 | (별 axis priority — pending) | [carve-out boundary + activation gate](IMP-17-CARVE-OUT.md) (3-cond AND: User GO ∧ B4 frame_selection evidence ∧ IMP-04/05 live — full def in u2 doc) — `httpx` + SSE streaming + retry + JSON parse pattern reference — light_edit / restructure proposal | **normal path AI 호출 0 — 본 axis = fallback only, normal path 와 분리 설계** / Kei persona 단절 (Phase Q 자산과 단절) | soft link: IMP-04 + IMP-05 (catalog 확장 + V4 fallback 활성 시 의미) | pending |
 | IMP-18 | I3 SVG 좌표 보강 | Step 0, 9 | §3 Reference Only | ↓ low | `renderer._preprocess_svg_data` 패턴 reference — frame_partials SVG 좌표 사전 박힘 | Phase R' (renderer.py) 회귀 X | soft link: IMP-04 (frame_partials 등록 후 의미 ↑) | pending |
 | IMP-19 | I4 zone 비중 분배 | Step 8 | §3 Reference Only | ↓ low | `renderer._group_blocks_by_area` 패턴 reference — zone-level ratio 분배 | Phase O 컨테이너 회귀 X / 직접 통합 X | soft link: IMP-09 (zone 비중 분배 영역 공유) | pending |
 | IMP-20 | H2 frame contract validation | Step 10 | §3 Reference Only | ↓ low | `content_verifier.verify_structure` pattern reference — Phase Z frame contract 검증 pattern | Phase Q `REQUIRED_PATTERNS` 값 회귀 X / Phase Z 자체 pattern dict 설계 | soft link: IMP-04 (확장 catalog 적용 시 검증 범위 확대) | pending |