Initial commit: clean project structure

- Backend: FastAPI + SQLAlchemy + Celery (Python 3.11+)
- Frontend: Vue 3 + TypeScript + Pinia + Tailwind
- Admin Frontend: separate Vue 3 app for management
- Docker Compose: 9 services orchestration
- Specs: design prototypes, memory system PRD, product roadmap

Cleanup performed:
- Removed temporary debug scripts from backend root
- Removed deprecated admin_app.py (embedded UI)
- Removed duplicate docs from admin-frontend
- Updated .gitignore for Vite cache and egg-info

backend/app/main.py

@@ -0,0 +1,80 @@
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api import (
+    auth,
+    memories,
+    profiles,
+    push_configs,
+    reading_events,
+    stories,
+    universes,
+)
+from app.core.config import settings
+from app.core.logging import get_logger, setup_logging
+from app.db.database import init_db
+
+setup_logging()
+logger = get_logger(__name__)
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """App lifespan manager."""
+    logger.info("app_starting", app_name=settings.app_name)
+    await init_db()
+    logger.info("database_initialized")
+
+    # 加载 provider 缓存
+    await _load_provider_cache()
+
+    yield
+    logger.info("app_shutdown")
+
+
+async def _load_provider_cache():
+    """启动时加载 provider 缓存。"""
+    from app.db.database import _get_session_factory
+    from app.services.provider_cache import reload_providers
+
+    try:
+        session_factory = _get_session_factory()
+        async with session_factory() as session:
+            cache = await reload_providers(session)
+            provider_count = sum(len(v) for v in cache.values())
+            logger.info("provider_cache_loaded", provider_count=provider_count)
+    except Exception as e:
+        logger.warning("provider_cache_load_failed", error=str(e))
+        # 不阻止启动，使用 settings 中的默认配置
+
+
+app = FastAPI(
+    title=settings.app_name,
+    description="AI-driven story generator for kids.",
+    version="0.1.0",
+    lifespan=lifespan,
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.cors_origins,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(auth.router, prefix="/auth", tags=["auth"])
+app.include_router(stories.router, prefix="/api", tags=["stories"])
+app.include_router(profiles.router, prefix="/api", tags=["profiles"])
+app.include_router(universes.router, prefix="/api", tags=["universes"])
+app.include_router(push_configs.router, prefix="/api", tags=["push-configs"])
+app.include_router(reading_events.router, prefix="/api", tags=["reading-events"])
+app.include_router(memories.router, prefix="/api", tags=["memories"])
+
+
+@app.get("/health")
+async def health_check():
+    """Simple liveness check."""
+    return {"status": "ok"}