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>

gpu-server/docker-compose.yml

@@ -0,0 +1,33 @@
+version: '3.8'
+
+services:
+  ollama:
+    image: ollama/ollama
+    volumes:
+      - ollama_data:/root/.ollama
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: nvidia
+              count: 1
+              capabilities: [gpu]
+    ports:
+      - "11434:11434"
+    restart: unless-stopped
+
+  ai-gateway:
+    build: ./services/ai-gateway
+    ports:
+      - "8080:8080"
+    environment:
+      - PRIMARY_ENDPOINT=${PRIMARY_ENDPOINT:-http://mac-mini:8800/v1/chat/completions}
+      - FALLBACK_ENDPOINT=http://ollama:11434/v1/chat/completions
+      - CLAUDE_API_KEY=${CLAUDE_API_KEY:-}
+      - DAILY_BUDGET_USD=${DAILY_BUDGET_USD:-5.00}
+    depends_on:
+      - ollama
+    restart: unless-stopped
+
+volumes:
+  ollama_data:

gpu-server/services/ai-gateway/Dockerfile

@@ -0,0 +1,10 @@
+FROM python:3.11-slim
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY server.py .
+
+CMD ["uvicorn", "server:app", "--host", "0.0.0.0", "--port", "8080"]

gpu-server/services/ai-gateway/requirements.txt

@@ -0,0 +1,3 @@
+fastapi>=0.110.0
+uvicorn[standard]>=0.27.0
+httpx>=0.27.0

gpu-server/services/ai-gateway/server.py

@@ -0,0 +1,58 @@
+"""AI Gateway — 모델 라우팅, 폴백, 비용 제어, 요청 로깅"""
+
+import os
+from datetime import date
+
+from fastapi import FastAPI, HTTPException, Request
+from fastapi.responses import JSONResponse
+import httpx
+
+app = FastAPI(title="AI Gateway", version="1.0.0")
+
+PRIMARY = os.getenv("PRIMARY_ENDPOINT", "http://localhost:8800/v1/chat/completions")
+FALLBACK = os.getenv("FALLBACK_ENDPOINT", "http://localhost:11434/v1/chat/completions")
+CLAUDE_API_KEY = os.getenv("CLAUDE_API_KEY", "")
+DAILY_BUDGET = float(os.getenv("DAILY_BUDGET_USD", "5.00"))
+
+# 일일 비용 추적 (메모리, 재시작 시 리셋)
+_daily_cost: dict[str, float] = {}
+_http = httpx.AsyncClient(timeout=120)
+
+
+@app.get("/health")
+async def health():
+    return {"status": "ok", "service": "ai-gateway"}
+
+
+@app.post("/v1/chat/completions")
+async def chat_completions(request: Request):
+    """OpenAI 호환 채팅 엔드포인트 — 자동 폴백"""
+    body = await request.json()
+    tier = request.headers.get("x-model-tier", "primary")
+
+    if tier == "premium":
+        return await _call_premium(body)
+
+    # Primary → Fallback 폴백
+    try:
+        resp = await _http.post(PRIMARY, json=body, timeout=60)
+        resp.raise_for_status()
+        return JSONResponse(content=resp.json())
+    except (httpx.TimeoutException, httpx.ConnectError, httpx.HTTPStatusError):
+        # 폴백
+        resp = await _http.post(FALLBACK, json=body, timeout=120)
+        resp.raise_for_status()
+        return JSONResponse(content=resp.json())
+
+
+async def _call_premium(body: dict):
+    """Claude API 호출 — 비용 제어"""
+    today = date.today().isoformat()
+    if _daily_cost.get(today, 0) >= DAILY_BUDGET:
+        raise HTTPException(429, f"일일 예산 초과: ${DAILY_BUDGET}")
+
+    if not CLAUDE_API_KEY:
+        raise HTTPException(503, "CLAUDE_API_KEY 미설정")
+
+    # TODO: Anthropic API 호출 + 비용 계산 (Phase 3에서 구현)
+    raise HTTPException(501, "Premium 모델 호출은 Phase 3에서 구현")