feat: CONAI Phase 1 MVP 초기 구현

소형 건설업체(100억 미만)를 위한 AI 기반 토목공사 통합관리 플랫폼

Backend (FastAPI):
- SQLAlchemy 모델 13개 (users, projects, wbs, tasks, daily_reports, reports, inspections, quality, weather, permits, rag, settings)
- API 라우터 11개 (auth, projects, tasks, daily_reports, reports, inspections, weather, rag, kakao, permits, settings)
- Services: Claude AI 래퍼, CPM Gantt 계산, 기상청 API, RAG(pgvector), 카카오 Skill API
- Alembic 마이그레이션 (pgvector 포함)
- pytest 테스트 (CPM, 날씨 경보)

Frontend (Next.js 15):
- 11개 페이지 (대시보드, 프로젝트, Gantt, 일보, 검측, 품질, 날씨, 인허가, RAG, 설정)
- TanStack Query + Zustand + Tailwind CSS

인프라:
- Docker Compose (PostgreSQL pgvector + backend + frontend)
- 한국어 README 및 설치 가이드

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/core/security.py

@@ -0,0 +1,38 @@
+from datetime import datetime, timedelta, timezone
+from typing import Optional, Any
+from jose import JWTError, jwt
+from passlib.context import CryptContext
+from app.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    return pwd_context.hash(password)
+
+
+def create_access_token(subject: Any, expires_delta: Optional[timedelta] = None) -> str:
+    if expires_delta:
+        expire = datetime.now(timezone.utc) + expires_delta
+    else:
+        expire = datetime.now(timezone.utc) + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    to_encode = {"exp": expire, "sub": str(subject), "type": "access"}
+    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+
+def create_refresh_token(subject: Any) -> str:
+    expire = datetime.now(timezone.utc) + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)
+    to_encode = {"exp": expire, "sub": str(subject), "type": "refresh"}
+    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+
+def decode_token(token: str) -> dict:
+    try:
+        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
+        return payload
+    except JWTError:
+        return {}