feat: home-gateway 초기 구성 — Mac mini에서 GPU 서버로 전면 이전

OrbStack 라이선스 만료로 Mac mini Docker 서비스를 GPU 서버로 통합.
nginx → Caddy 전환, 12개 서브도메인 자동 HTTPS, fail2ban Caddy JSON 연동.

주요 변경:
- home-caddy: Caddy 리버스 프록시 (Let's Encrypt 자동 HTTPS)
- home-fail2ban: Caddy JSON 로그 기반 보안 모니터링
- home-ddns: Cloudflare DDNS (API 키 .env 분리)
- gpu-hub-api/web: AI 백엔드 라우터 + 웹 UI (gpu-services에서 이전)
- AI 런타임(Ollama) 내부망 전용, 외부는 gpu-hub 인증 게이트웨이 경유

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

hub-api/main.py

@@ -0,0 +1,46 @@
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from config import settings
+from middleware.auth import AuthMiddleware
+from routers import auth, chat, embeddings, gpu, health, models
+from services.registry import registry
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    await registry.load_backends(settings.backends_config)
+    registry.start_health_loop()
+    yield
+    registry.stop_health_loop()
+
+
+app = FastAPI(
+    title="AI Gateway",
+    version="0.1.0",
+    lifespan=lifespan,
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.cors_origins.split(","),
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.add_middleware(AuthMiddleware)
+
+app.include_router(auth.router)
+app.include_router(chat.router)
+app.include_router(models.router)
+app.include_router(embeddings.router)
+app.include_router(health.router)
+app.include_router(gpu.router)
+
+
+@app.get("/")
+async def root():
+    return {"service": "AI Gateway", "version": "0.1.0"}