feat(phase-1): Complete foundation setup

- Add User model and authentication system with JWT cookies
- Implement login/logout routes and protected dashboard
- Add Alembic database migration configuration
- Add create_admin.py script for initial user setup
- Make ContentGenerator and ImageGenerator lazy-initialized
- Add comprehensive API keys setup documentation
- Fix startup errors when services unavailable

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/main.py

@@ -5,17 +5,27 @@ Sistema automatizado para la creación y publicación de contenido
 en redes sociales (X, Threads, Instagram, Facebook).
 """
 
+from contextlib import asynccontextmanager
+
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
 from fastapi.middleware.cors import CORSMiddleware
 
-from app.api.routes import posts, products, services, calendar, dashboard, interactions
+from app.api.routes import posts, products, services, calendar, dashboard, interactions, auth
 from app.core.config import settings
 from app.core.database import engine
 from app.models import Base
 
-# Crear tablas en la base de datos
-Base.metadata.create_all(bind=engine)
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Lifecycle manager - crea tablas al iniciar si hay conexión a BD."""
+    try:
+        Base.metadata.create_all(bind=engine)
+    except Exception as e:
+        print(f"⚠️  No se pudo conectar a BD: {e}")
+        print("   La app funcionará pero sin persistencia hasta configurar BD")
+    yield
 
 # Inicializar aplicación FastAPI
 app = FastAPI(
@@ -24,6 +34,7 @@ app = FastAPI(
     version="1.0.0",
     docs_url="/api/docs",
     redoc_url="/api/redoc",
+    lifespan=lifespan,
 )
 
 # Configurar CORS
@@ -39,6 +50,7 @@ app.add_middleware(
 app.mount("/static", StaticFiles(directory="dashboard/static"), name="static")
 
 # Registrar rutas
+app.include_router(auth.router, prefix="", tags=["Auth"])
 app.include_router(dashboard.router, prefix="", tags=["Dashboard"])
 app.include_router(posts.router, prefix="/api/posts", tags=["Posts"])
 app.include_router(products.router, prefix="/api/products", tags=["Products"])