feat: scaffold v2 project structure with Docker, FastAPI, and config

동작하는 최소 코드 수준의 v2 스캐폴딩:

- docker-compose.yml: postgres, fastapi, kordoc, frontend, caddy
- app/: FastAPI 백엔드 (main, core, models, ai, prompts)
- services/kordoc/: Node.js 문서 파싱 마이크로서비스
- gpu-server/: AI Gateway + GPU docker-compose
- frontend/: SvelteKit 기본 구조
- migrations/: PostgreSQL 초기 스키마 (documents, tasks, processing_queue)
- tests/: pytest conftest 기본 설정
- config.yaml, Caddyfile, credentials.env.example 갱신

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/conftest.py

@@ -0,0 +1,22 @@
+"""pytest 기본 fixture 설정"""
+
+import pytest
+import pytest_asyncio
+from httpx import ASGITransport, AsyncClient
+
+
+@pytest.fixture(scope="session")
+def anyio_backend():
+    return "asyncio"
+
+
+# TODO: Phase 0 완료 후 활성화
+# @pytest_asyncio.fixture
+# async def client():
+#     """FastAPI 테스트 클라이언트"""
+#     from app.main import app
+#     async with AsyncClient(
+#         transport=ASGITransport(app=app),
+#         base_url="http://test"
+#     ) as ac:
+#         yield ac