feat(search): cloud-egress allowlist gate for cloud consumers (gap2)

클라우드 소비자(Claude/MCP)에 cloud-eligibility allowlist 강제 — DS 접근규격 갭2.
- auth: create_access_token egress claim(기본 local·비파괴) + get_egress_class 의존성
- AxisFilter.cloud_egress + _axis_sql allowlist 술어(토큰 claim 유래·쿼리파라미터 아님=우회불가)
- 규칙: external OR (work ∩ bucket∈{Eng,Safety,Law} ∩ ∉{voice,chat,memo} ∩ ≠memo ∩ user_note없음)
검증(cloud vs local): 인프라알림([Hyungi_NAS] tk-*api)·work/Programming(리디북스) 차단,
work/Engineering(hoop stress·ASME) 통과, external 통과. local=전부(무회귀).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/api/search.py

@@ -15,7 +15,7 @@ from fastapi.responses import JSONResponse
 from pydantic import BaseModel
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from core.auth import get_current_user
+from core.auth import get_current_user, get_egress_class
 from core.database import get_session
 from core.utils import setup_logger
 from models.user import User
@@ -139,6 +139,7 @@ def _build_search_debug(pr: PipelineResult) -> SearchDebug:
 async def search(
     q: str,
     user: Annotated[User, Depends(get_current_user)],
+    egress_class: Annotated[str, Depends(get_egress_class)],
     session: Annotated[AsyncSession, Depends(get_session)],
     background_tasks: BackgroundTasks,
     mode: str = Query("hybrid", pattern="^(fts|trgm|vector|hybrid)$"),
@@ -225,6 +226,7 @@ async def search(
             year_to=year_to,
             domain_buckets=[b.strip() for b in domain_bucket.split(",") if b.strip()] if domain_bucket else None,
             exclude_buckets=[b.strip() for b in exclude_bucket.split(",") if b.strip()] if exclude_bucket else None,
+            cloud_egress=(egress_class == "cloud"),
         )
         pr = await run_search(
             session,