feat: Initialize FastAPI AI Gateway project structure with authentication, module management, and LLM API routing.

app/api/router.py

@@ -0,0 +1,7 @@
+from fastapi import APIRouter
+from app.api.endpoints import storyline, gemini, openai
+
+api_router = APIRouter()
+api_router.include_router(storyline.router, prefix="/storyline", tags=["storyline"])
+api_router.include_router(gemini.router, prefix="/gemini", tags=["gemini"])
+api_router.include_router(openai.router, prefix="/openai", tags=["openai"])