chore: initial project setup with backend, frontend, CI/CD, and documentation

Add complete NexaFabric project structure including:
- FastAPI backend with SQLAlchemy models, JWT auth, RBAC, audit logging, and provider interfaces
- React + TypeScript frontend with Vite, Tailwind CSS, TanStack Query, and Zustand
- Docker Compose configuration for PostgreSQL, Redis, API, worker, frontend, and nginx
- GitHub Actions and GitLab CI workflows for testing, linting, building, and security scanning
- Environment

backend/app/api/v1/auth.py

@@ -0,0 +1,44 @@
+from datetime import datetime
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from app.api.deps import CurrentUser
+from app.core.security import create_access_token, create_refresh_token, verify_password
+from app.db.session import get_db
+from app.models.domain import User
+from app.schemas.domain import LoginRequest, TokenPair, UserRead
+from app.services.audit import write_audit
+
+router = APIRouter(prefix="/auth", tags=["auth"])
+
+
+@router.post("/login", response_model=TokenPair)
+def login(payload: LoginRequest, db: Session = Depends(get_db)) -> TokenPair:
+    user = db.scalar(select(User).where(User.email == payload.email))
+    if not user or not verify_password(payload.password, user.password_hash):
+        if user:
+            user.failed_login_attempts += 1
+            db.commit()
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid credentials")
+    permissions = sorted({permission for role in user.roles for permission in role.permissions})
+    user.failed_login_attempts = 0
+    db.commit()
+    write_audit(db, action="login", object_type="user", object_id=user.id, user_id=user.id)
+    return TokenPair(
+        access_token=create_access_token(user.id, permissions),
+        refresh_token=create_refresh_token(user.id),
+    )
+
+
+@router.get("/me", response_model=UserRead)
+def me(user: CurrentUser) -> User:
+    return user
+
+
+@router.post("/logout")
+def logout(user: CurrentUser, db: Session = Depends(get_db)) -> dict[str, str]:
+    write_audit(db, action="logout", object_type="user", object_id=user.id, user_id=user.id)
+    return {"status": "ok", "at": datetime.utcnow().isoformat()}
+